diff --git a/src/renderer/src/components/editor/ExternalFileChangeBanner.test.tsx b/src/renderer/src/components/editor/ExternalFileChangeBanner.test.tsx
index d48cf186e6d..9021244b904 100644
--- a/src/renderer/src/components/editor/ExternalFileChangeBanner.test.tsx
+++ b/src/renderer/src/components/editor/ExternalFileChangeBanner.test.tsx
@@ -30,8 +30,9 @@ import {
   keepTabEditsOverExternalChange,
   reloadTabContentFromDisk
 } from './ExternalFileChangeBanner'
-import { getDiskBaselineSignature } from './diff-content-signature'
+import { getDiskBaselineSignature } from '../../../../shared/disk-baseline-signature'
 import { useAppStore } from '@/store'
+import { createTestStore } from '@/store/slices/store-test-helpers'
 
 const file = {
   id: 'file-1',
@@ -52,15 +53,15 @@ describe('ExternalFileChangeBanner', () => {
 
   function mockStoreState(editorDrafts: Record<string, string>, openFiles: OpenFile[] = [file]) {
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       clearEditorDraft,
       markFileDirty,
       setExternalMutation,
       setEditorDraft,
       setLastKnownDiskSignature,
       editorDrafts,
-      openFiles,
-      settings: {}
-    } as never)
+      openFiles
+    })
   }
 
   beforeEach(() => {
diff --git a/src/renderer/src/components/editor/ExternalFileChangeBanner.tsx b/src/renderer/src/components/editor/ExternalFileChangeBanner.tsx
index bf91d5e1513..cbc840ba641 100644
--- a/src/renderer/src/components/editor/ExternalFileChangeBanner.tsx
+++ b/src/renderer/src/components/editor/ExternalFileChangeBanner.tsx
@@ -10,7 +10,7 @@ import { useAppStore } from '@/store'
 import { translate } from '@/i18n/i18n'
 import type { OpenFile } from '@/store/slices/editor'
 import { ExternalFileChangeCompareDialog } from './ExternalFileChangeCompareDialog'
-import { getDiskBaselineSignature } from './diff-content-signature'
+import { getDiskBaselineSignature } from '../../../../shared/disk-baseline-signature'
 import { trackExternalChangeConflictAction } from './editor-external-change-telemetry'
 import { attemptEditorFileSave } from './editor-file-save-attempt'
 import {
diff --git a/src/renderer/src/components/editor/diff-content-signature.ts b/src/renderer/src/components/editor/diff-content-signature.ts
index 9c74a207818..927d9711d89 100644
--- a/src/renderer/src/components/editor/diff-content-signature.ts
+++ b/src/renderer/src/components/editor/diff-content-signature.ts
@@ -9,6 +9,3 @@ export function getDiffContentSignature(content: string): string {
   }
   return (hash >>> 0).toString(16)
 }
-
-// Why shared: the writer that refuses a stale save hashes disk with this same function.
-export { getDiskBaselineSignature } from '../../../../shared/disk-baseline-signature'
diff --git a/src/renderer/src/components/editor/editor-changed-on-disk-mark.ts b/src/renderer/src/components/editor/editor-changed-on-disk-mark.ts
index f8c49331b1d..bbb54cdac58 100644
--- a/src/renderer/src/components/editor/editor-changed-on-disk-mark.ts
+++ b/src/renderer/src/components/editor/editor-changed-on-disk-mark.ts
@@ -1,12 +1,9 @@
+import type { AppState } from '@/store'
 import type { OpenFile } from '@/store/slices/editor'
 import { canAutoSaveOpenFile } from './editor-autosave'
-import { editorModelSiblingTabs, isWholeEditorState } from './editor-save-disk-precondition'
+import { editorModelSiblingTabs } from './editor-save-disk-precondition'
 import { trackExternalChangeConflictShown } from './editor-external-change-telemetry'
 
-type ChangedOnDiskMarkState = {
-  setExternalMutation: (fileId: string, mutation: 'deleted' | 'renamed' | 'changed' | null) => void
-}
-
 // Why: the changed-on-disk mark has one rule — dirty, banner-capable tab,
 // telemetry only on the first surfacing — but three writers (the watch hook
 // at fs-event time, the autosave controller's notification backstop, and the
@@ -14,15 +11,13 @@ type ChangedOnDiskMarkState = {
 // each writer keeps its own echo/eligibility guard at the call site. A code
 // model is dirty when any of its tabs is, and the mark reaches all of them.
 export function markFileChangedOnDisk(
-  state: ChangedOnDiskMarkState,
+  state: AppState,
   file: OpenFile,
   options: { connectionId: string | undefined; origin: 'live' | 'restore' }
 ): void {
-  // Why: some writers pass only the setter; the model's other tabs are known only from the whole store.
-  const tabs =
-    isWholeEditorState(state) && state.openFiles.some((tab) => tab.id === file.id)
-      ? editorModelSiblingTabs(state, file)
-      : [file]
+  const tabs = state.openFiles.some((tab) => tab.id === file.id)
+    ? editorModelSiblingTabs(state, file)
+    : [file]
   if (!tabs.some((tab) => tab.isDirty) || !canAutoSaveOpenFile(file)) {
     return
   }
diff --git a/src/renderer/src/components/editor/editor-clean-tab-disk-baseline.ts b/src/renderer/src/components/editor/editor-clean-tab-disk-baseline.ts
index b9dde358223..05a32b3499b 100644
--- a/src/renderer/src/components/editor/editor-clean-tab-disk-baseline.ts
+++ b/src/renderer/src/components/editor/editor-clean-tab-disk-baseline.ts
@@ -1,7 +1,7 @@
 import { useAppStore, type AppState } from '@/store'
 import type { OpenFile } from '@/store/slices/editor'
 import { isEditorContentUnchanged } from './editor-content-dirty-state'
-import { getDiskBaselineSignature } from './diff-content-signature'
+import { getDiskBaselineSignature } from '../../../../shared/disk-baseline-signature'
 import type { FileContent } from './editor-panel-content-types'
 import {
   editorModelSiblingTabs,
diff --git a/src/renderer/src/components/editor/editor-restored-tab-conflict-scan.recheck.test.ts b/src/renderer/src/components/editor/editor-restored-tab-conflict-scan.recheck.test.ts
index f852f793b1c..d4e3abb235a 100644
--- a/src/renderer/src/components/editor/editor-restored-tab-conflict-scan.recheck.test.ts
+++ b/src/renderer/src/components/editor/editor-restored-tab-conflict-scan.recheck.test.ts
@@ -27,7 +27,7 @@ import {
   MAX_VERIFY_ATTEMPTS,
   requestRestoredTabReverification
 } from './editor-restored-tab-conflict-scan'
-import { getDiskBaselineSignature } from './diff-content-signature'
+import { getDiskBaselineSignature } from '../../../../shared/disk-baseline-signature'
 
 const FILE = '/repo/a.ts'
 let store: ReturnType<typeof createTestStore>
@@ -84,6 +84,35 @@ it('reads once more when a new check is requested while a read is in flight', as
   expect(tab().pendingDiskBaselineVerification).toBeFalsy()
 })
 
+it.each([
+  { disk: 'v1', banner: undefined },
+  { disk: 'v2 external write', banner: 'changed' }
+])('waits out overlapping checks, then judges a fresh read ($disk)', async ({ disk, banner }) => {
+  const replies: ((content: string) => void)[] = []
+  mocks.readRuntimeFileContent.mockImplementation(
+    () => new Promise((resolve) => replies.push((content) => resolve({ content, isBinary: false })))
+  )
+  store.getState().setPendingDiskBaselineVerification(fileId, true)
+  detach = attachRestoredTabConflictScan(store)
+  await vi.advanceTimersByTimeAsync(0)
+  expect(replies).toHaveLength(1)
+
+  // Every read is slower than the re-verify interval, so a newer check always lands first.
+  for (let i = 0; i < MAX_VERIFY_ATTEMPTS + 5; i += 1) {
+    requestRestoredTabReverification(fileId)
+    replies[i]('v1')
+    await vi.advanceTimersByTimeAsync(60_000)
+    expect(replies).toHaveLength(i + 2)
+  }
+  expect(tab().pendingDiskBaselineVerification).toBe(true)
+  expect(tab().externalMutation).toBeUndefined()
+
+  replies.at(-1)!(disk)
+  await vi.advanceTimersByTimeAsync(0)
+  expect(tab().pendingDiskBaselineVerification).toBeFalsy()
+  expect(tab().externalMutation).toBe(banner)
+})
+
 it('marks a dirty runtime-owned tab deleted when its host says the file is gone', async () => {
   mocks.readRuntimeFileContent.mockRejectedValue(new Error('read failed'))
   mocks.runtimePathsExist.mockResolvedValue([{ exists: false }])
diff --git a/src/renderer/src/components/editor/editor-restored-tab-conflict-scan.test.ts b/src/renderer/src/components/editor/editor-restored-tab-conflict-scan.test.ts
index 73a8172b70c..922d1dd2777 100644
--- a/src/renderer/src/components/editor/editor-restored-tab-conflict-scan.test.ts
+++ b/src/renderer/src/components/editor/editor-restored-tab-conflict-scan.test.ts
@@ -1,10 +1,10 @@
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
-import { createStore, type StoreApi } from 'zustand/vanilla'
-import { createEditorSlice } from '@/store/slices/editor'
+import type { StoreApi } from 'zustand/vanilla'
+import { createTestStore } from '@/store/slices/store-test-helpers'
 import { FLOATING_TERMINAL_WORKTREE_ID } from '../../../../shared/constants'
 import type { AppState } from '@/store'
 import { attachRestoredTabConflictScan } from './editor-restored-tab-conflict-scan'
-import { getDiskBaselineSignature } from './diff-content-signature'
+import { getDiskBaselineSignature } from '../../../../shared/disk-baseline-signature'
 
 const mocks = vi.hoisted(() => ({
   readRuntimeFileContent: vi.fn(),
@@ -20,14 +20,6 @@ vi.mock('@/lib/connection-context', () => ({
   getConnectionIdForFile: mocks.getConnectionIdForFile
 }))
 
-function createEditorStore(): StoreApi<AppState> {
-  // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  return createStore<any>()((...args: any[]) => ({
-    settings: {},
-    ...createEditorSlice(...(args as Parameters<typeof createEditorSlice>))
-  })) as unknown as StoreApi<AppState>
-}
-
 function openRestoredDirtyTab(
   store: StoreApi<AppState>,
   filePath: string,
@@ -71,7 +63,7 @@ describe('attachRestoredTabConflictScan', () => {
       content: 'agent rewrote this offline',
       isBinary: false
     })
-    const store = createEditorStore()
+    const store = createTestStore()
     openRestoredDirtyTab(store, '/repo/file.ts', 'original baseline')
 
     const detach = attachRestoredTabConflictScan(store)
@@ -88,7 +80,7 @@ describe('attachRestoredTabConflictScan', () => {
       content: 'original baseline',
       isBinary: false
     })
-    const store = createEditorStore()
+    const store = createTestStore()
     openRestoredDirtyTab(store, '/repo/file.ts', 'original baseline')
 
     const detach = attachRestoredTabConflictScan(store)
@@ -102,7 +94,7 @@ describe('attachRestoredTabConflictScan', () => {
   })
 
   it('does not read files for clean tabs or tabs without a baseline', async () => {
-    const store = createEditorStore()
+    const store = createTestStore()
     store.getState().openFile({
       filePath: '/repo/clean.ts',
       relativePath: 'clean.ts',
@@ -134,7 +126,7 @@ describe('attachRestoredTabConflictScan', () => {
     mocks.readRuntimeFileContent
       .mockRejectedValueOnce(new Error('connection not ready'))
       .mockResolvedValue({ content: 'agent rewrote this offline', isBinary: false })
-    const store = createEditorStore()
+    const store = createTestStore()
     openRestoredDirtyTab(store, '/repo/file.ts', 'original baseline')
 
     const detach = attachRestoredTabConflictScan(store)
@@ -153,7 +145,7 @@ describe('attachRestoredTabConflictScan', () => {
       content: 'original baseline',
       isBinary: false
     })
-    const store = createEditorStore()
+    const store = createTestStore()
     openRestoredDirtyTab(store, '/repo/match.ts', 'original baseline')
 
     const detach = attachRestoredTabConflictScan(store)
@@ -178,7 +170,7 @@ describe('attachRestoredTabConflictScan', () => {
   })
 
   it('does not re-verify live dirty tabs that were never flagged at hydration', async () => {
-    const store = createEditorStore()
+    const store = createTestStore()
     store.getState().openFile({
       filePath: '/repo/live.ts',
       relativePath: 'live.ts',
@@ -207,7 +199,7 @@ describe('attachRestoredTabConflictScan', () => {
     // suspended for the whole session.
     mocks.readRuntimeFileContent.mockRejectedValue(new Error('ENOENT'))
     mocks.pathExists.mockResolvedValue(false)
-    const store = createEditorStore()
+    const store = createTestStore()
     openRestoredDirtyTab(store, '/repo/deleted.ts', 'original baseline')
 
     const detach = attachRestoredTabConflictScan(store)
@@ -230,7 +222,7 @@ describe('attachRestoredTabConflictScan', () => {
     // transport recovers.
     mocks.readRuntimeFileContent.mockRejectedValue(new Error('connection not ready'))
     mocks.pathExists.mockRejectedValue(new Error('connection not ready'))
-    const store = createEditorStore()
+    const store = createTestStore()
     openRestoredDirtyTab(store, '/repo/unreachable.ts', 'original baseline')
 
     const detach = attachRestoredTabConflictScan(store)
@@ -254,7 +246,7 @@ describe('attachRestoredTabConflictScan', () => {
     })
     mocks.pathExists.mockResolvedValue(true)
     mocks.getConnectionIdForFile.mockReturnValue(null)
-    const store = createEditorStore()
+    const store = createTestStore()
     openRestoredDirtyTab(store, '/Users/me/notes.txt', 'original baseline', {
       relativePath: 'notes.txt',
       worktreeId: FLOATING_TERMINAL_WORKTREE_ID
@@ -282,7 +274,7 @@ describe('attachRestoredTabConflictScan', () => {
       isBinary: false
     })
     mocks.getConnectionIdForFile.mockReturnValue(null)
-    const store = createEditorStore()
+    const store = createTestStore()
     openRestoredDirtyTab(store, '/repo/file.ts', 'original baseline')
 
     const detach = attachRestoredTabConflictScan(store)
@@ -297,7 +289,7 @@ describe('attachRestoredTabConflictScan', () => {
   })
 
   it('does not verify an external SSH file through a replacement target', async () => {
-    const store = createEditorStore()
+    const store = createTestStore()
     openRestoredDirtyTab(store, '/tmp/external.ts', 'original baseline')
     store.setState({
       openFiles: store
@@ -328,7 +320,7 @@ describe('attachRestoredTabConflictScan', () => {
           pendingReads.push(resolve)
         })
     )
-    const store = createEditorStore()
+    const store = createTestStore()
     for (let i = 0; i < 6; i++) {
       openRestoredDirtyTab(store, `/repo/file-${i}.ts`, 'original baseline')
     }
@@ -361,7 +353,7 @@ describe('attachRestoredTabConflictScan', () => {
         resolveRead = resolve
       })
     )
-    const store = createEditorStore()
+    const store = createTestStore()
     openRestoredDirtyTab(store, '/repo/file.ts', 'original baseline')
 
     const detach = attachRestoredTabConflictScan(store)
@@ -390,7 +382,7 @@ describe('attachRestoredTabConflictScan', () => {
           pending.push({ filePath, resolve })
         })
     )
-    const store = createEditorStore()
+    const store = createTestStore()
     // Three reads fill the concurrency cap; the fourth waits in the queue.
     for (let i = 0; i < 4; i++) {
       openRestoredDirtyTab(store, `/repo/file-${i}.ts`, 'stale baseline')
diff --git a/src/renderer/src/components/editor/editor-restored-tab-conflict-scan.ts b/src/renderer/src/components/editor/editor-restored-tab-conflict-scan.ts
index ea889325a80..8b5943f03b6 100644
--- a/src/renderer/src/components/editor/editor-restored-tab-conflict-scan.ts
+++ b/src/renderer/src/components/editor/editor-restored-tab-conflict-scan.ts
@@ -10,7 +10,7 @@ import {
   requireRuntimeTargetForFileOwner
 } from '@/lib/file-owner-runtime-target'
 import { canAutoSaveOpenFile } from './editor-autosave'
-import { getDiskBaselineSignature } from './diff-content-signature'
+import { getDiskBaselineSignature } from '../../../../shared/disk-baseline-signature'
 import { markFileChangedOnDisk } from './editor-changed-on-disk-mark'
 import { runtimePathsExist } from '@/runtime/runtime-path-existence-batch'
 
@@ -60,6 +60,7 @@ export function attachRestoredTabConflictScan(store: AppStoreApi): () => void {
   // Dedupes queued + in-flight verifications; the store's pending flag is the durable "needs verification" signal.
   const inFlightFileIds = new Set<string>()
   const attemptsByFileId = new Map<string, number>()
+  const supersededReadsByFileId = new Map<string, number>()
   const retryTimers = new Set<ReturnType<typeof setTimeout>>()
   // Queue ids, not OpenFile snapshots: a snapshot can go stale (close/reopen or same-path save) while it waits for a slot.
   const verifyQueue: string[] = []
@@ -129,10 +130,18 @@ export function attachRestoredTabConflictScan(store: AppStoreApi): () => void {
     if (verifyRequestGeneration(fileId) === requestGeneration) {
       return false
     }
-    queueMicrotask(() => {
-      inFlightFileIds.delete(fileId)
-      scan()
-    })
+    // Why back off, not cap: a superseded answer may predate the newer check, so it never resolves; churn only delays the fresh read.
+    const superseded = (supersededReadsByFileId.get(fileId) ?? 0) + 1
+    supersededReadsByFileId.set(fileId, superseded)
+    const timer = setTimeout(
+      () => {
+        retryTimers.delete(timer)
+        inFlightFileIds.delete(fileId)
+        scan()
+      },
+      Math.min((superseded - 1) * VERIFY_RETRY_MS, VERIFY_SLOW_RETRY_MS)
+    )
+    retryTimers.add(timer)
     return true
   }
 
@@ -163,6 +172,7 @@ export function attachRestoredTabConflictScan(store: AppStoreApi): () => void {
         return
       }
       attemptsByFileId.delete(file.id)
+      supersededReadsByFileId.delete(file.id)
       // Verification resolved: lift autosave suspension regardless of outcome; wasPending flags a save that already re-baselined.
       const wasPending = liveFile.pendingDiskBaselineVerification === true
       store.getState().clearPendingDiskBaselineVerification(file.id)
@@ -233,6 +243,7 @@ export function attachRestoredTabConflictScan(store: AppStoreApi): () => void {
   // Why: still unverifiable after every retry; resume nothing silently — the banner makes the user choose.
   const giveUp = (file: OpenFile): void => {
     attemptsByFileId.delete(file.id)
+    supersededReadsByFileId.delete(file.id)
     const liveFile = store.getState().openFiles.find((f) => f.id === file.id)
     if (!liveFile?.pendingDiskBaselineVerification) {
       return
diff --git a/src/renderer/src/components/editor/editor-save-disk-precondition.ts b/src/renderer/src/components/editor/editor-save-disk-precondition.ts
index b6adeba877b..8112f02a690 100644
--- a/src/renderer/src/components/editor/editor-save-disk-precondition.ts
+++ b/src/renderer/src/components/editor/editor-save-disk-precondition.ts
@@ -85,17 +85,6 @@ export function editorModelDraftHolder(state: AppState, file: OpenFile): OpenFil
   )
 }
 
-/** Whether a store snapshot is whole enough to resolve a tab's model siblings. */
-export function isWholeEditorState(state: unknown): state is AppState {
-  return (
-    typeof state === 'object' &&
-    state !== null &&
-    'editorDrafts' in state &&
-    'worktreesByRepo' in state &&
-    'setLastKnownDiskSignature' in state
-  )
-}
-
 /**
  * The one disk version of a code-view model: every tab sharing the model holds the same value, set
  * only here. Other views keep their own. Returns the sibling tabs whose value moved.
diff --git a/src/renderer/src/components/editor/editor-save-queue.ts b/src/renderer/src/components/editor/editor-save-queue.ts
index 7bb5cde7f82..de0aa062673 100644
--- a/src/renderer/src/components/editor/editor-save-queue.ts
+++ b/src/renderer/src/components/editor/editor-save-queue.ts
@@ -16,7 +16,7 @@ import {
   recordSelfWrite,
   SELF_WRITE_REMOTE_TTL_MS
 } from './editor-self-write-registry'
-import { getDiskBaselineSignature } from './diff-content-signature'
+import { getDiskBaselineSignature } from '../../../../shared/disk-baseline-signature'
 import { trackExternalChangeConflictAction } from './editor-external-change-telemetry'
 import { editorTabFileAccess } from '@/lib/local-file-access'
 import { isEditorLargePasteInFlight } from './editor-large-paste-in-flight'
diff --git a/src/renderer/src/components/editor/editor-stale-mount-guard.ts b/src/renderer/src/components/editor/editor-stale-mount-guard.ts
index afd3241de59..b8b5f2a4e05 100644
--- a/src/renderer/src/components/editor/editor-stale-mount-guard.ts
+++ b/src/renderer/src/components/editor/editor-stale-mount-guard.ts
@@ -1,7 +1,7 @@
 import { useAppStore } from '@/store'
 import { getDiskBaselineSignature } from '../../../../shared/disk-baseline-signature'
 import { notifyEditorFileCacheStale } from './editor-autosave'
-import { isEditorModelDirty, isWholeEditorState } from './editor-save-disk-precondition'
+import { isEditorModelDirty } from './editor-save-disk-precondition'
 
 /**
  * A clean tab's text (cache, or a leftover draft) that no longer matches its disk version, such as
@@ -49,9 +49,6 @@ export function settleStaleCacheReload(fileId: string): void {
  */
 export function mayPushTabTextIntoModel(fileId: string): boolean {
   const state = useAppStore.getState()
-  if (!isWholeEditorState(state)) {
-    return true
-  }
   const file = state.openFiles.find((openFile) => openFile.id === fileId)
   if (!file || file.isDirty) {
     // Why: a dirty tab's text is its own edits.
diff --git a/src/renderer/src/components/editor/editor-untitled-dont-save-dialogs.test.tsx b/src/renderer/src/components/editor/editor-untitled-dont-save-dialogs.test.tsx
index ece6409c8eb..25d563448a4 100644
--- a/src/renderer/src/components/editor/editor-untitled-dont-save-dialogs.test.tsx
+++ b/src/renderer/src/components/editor/editor-untitled-dont-save-dialogs.test.tsx
@@ -8,7 +8,7 @@ import {
   createUntitledNoteStore,
   type FakeEditorDisk
 } from './editor-autosave-controller-test-fixture'
-import { getDiskBaselineSignature } from './diff-content-signature'
+import { getDiskBaselineSignature } from '../../../../shared/disk-baseline-signature'
 import { useTerminalSaveDialog } from '../terminal/useTerminalSaveDialog'
 import {
   useTerminalEditorCloseDialogActions,
diff --git a/src/renderer/src/components/editor/editor-untitled-save-lifecycle.test.ts b/src/renderer/src/components/editor/editor-untitled-save-lifecycle.test.ts
index 38709333368..7afa7d76f00 100644
--- a/src/renderer/src/components/editor/editor-untitled-save-lifecycle.test.ts
+++ b/src/renderer/src/components/editor/editor-untitled-save-lifecycle.test.ts
@@ -12,7 +12,7 @@ import {
 } from './editor-autosave-controller-test-fixture'
 import { discardEditorFileChangesAndClose } from './discard-editor-file-changes'
 import { __clearSelfWriteRegistryForTests } from './editor-self-write-registry'
-import { getDiskBaselineSignature } from './diff-content-signature'
+import { getDiskBaselineSignature } from '../../../../shared/disk-baseline-signature'
 
 const storeHolder = vi.hoisted((): { store: StoreApi<AppState> | null } => ({ store: null }))
 
diff --git a/src/renderer/src/components/editor/use-monaco-editor-mount.cursor-owner.test.tsx b/src/renderer/src/components/editor/use-monaco-editor-mount.cursor-owner.test.tsx
index 667e3be7530..f430bc32562 100644
--- a/src/renderer/src/components/editor/use-monaco-editor-mount.cursor-owner.test.tsx
+++ b/src/renderer/src/components/editor/use-monaco-editor-mount.cursor-owner.test.tsx
@@ -4,13 +4,16 @@ import { Suspense } from 'react'
 import { afterEach, expect, it, vi } from 'vitest'
 import type { editor } from 'monaco-editor'
 import type { OnMount } from '@monaco-editor/react'
+import type { StoreApi } from 'zustand'
+import type { AppState } from '@/store'
 import { createEditorTabsStore } from '@/store/slices/editor-slice-test-harness'
 import { captureEditorFileOperationProvenance } from '@/lib/editor-file-operation-owner'
 import type { MonacoEditorMountParams } from './monaco-editor-mount-params'
 import { useMonacoEditorMount } from './use-monaco-editor-mount'
 
+const storeRef = vi.hoisted((): { current?: StoreApi<AppState> } => ({}))
 vi.mock('@/store', () => ({
-  useAppStore: { getState: () => ({ pendingEditorReveal: null, pendingEditorFocusRequest: null }) }
+  useAppStore: { getState: () => storeRef.current?.getState() }
 }))
 vi.mock('./monaco-markdown-doc-link-decorations', () => ({
   createMarkdownDocLinkDecorationController: vi.fn()
@@ -27,6 +30,7 @@ afterEach(cleanup)
 
 it('keeps a retained cursor listener on the current file ID after same-path owner migration', () => {
   const store = createEditorTabsStore()
+  storeRef.current = store
   const filePath = '/repo/file.ts'
   const oldId = 'restored-file'
   store.setState({
diff --git a/src/renderer/src/components/editor/useEditorPanelContentState.test.tsx b/src/renderer/src/components/editor/useEditorPanelContentState.test.tsx
index d7c84e81ee5..1615e34056b 100644
--- a/src/renderer/src/components/editor/useEditorPanelContentState.test.tsx
+++ b/src/renderer/src/components/editor/useEditorPanelContentState.test.tsx
@@ -68,7 +68,8 @@ vi.mock('@/store', () => ({
 }))
 
 import { useEditorPanelContentState } from './useEditorPanelContentState'
-import { getDiskBaselineSignature } from './diff-content-signature'
+import { createTestStore } from '@/store/slices/store-test-helpers'
+import { getDiskBaselineSignature } from '../../../../shared/disk-baseline-signature'
 import { ORCA_EDITOR_EXTERNAL_FILE_CHANGE_EVENT } from './editor-autosave'
 
 type Deferred<T> = {
@@ -166,6 +167,7 @@ describe('useEditorPanelContentState', () => {
     mocks.isWorktreeConnectionResolved.mockReturnValue(true)
     mocks.getState.mockReset()
     mocks.getState.mockReturnValue({
+      ...createTestStore().getState(),
       settings: null,
       openFiles: [],
       setLastKnownDiskSignature: vi.fn()
@@ -315,6 +317,7 @@ describe('useEditorPanelContentState', () => {
     })
     mocks.getConnectionIdForFile.mockReturnValue(undefined)
     mocks.getState.mockReturnValue({
+      ...createTestStore().getState(),
       settings: { activeRuntimeEnvironmentId: 'runtime-1' },
       openFiles: [],
       setLastKnownDiskSignature: vi.fn()
@@ -883,6 +886,7 @@ describe('useEditorPanelContentState', () => {
     const activeFile = createOpenFile()
     const setLastKnownDiskSignature = vi.fn()
     mocks.getState.mockReturnValue({
+      ...createTestStore().getState(),
       settings: null,
       openFiles: [activeFile],
       setLastKnownDiskSignature
@@ -911,6 +915,7 @@ describe('useEditorPanelContentState', () => {
     const activeFile = createOpenFile({ isDirty: true })
     const setLastKnownDiskSignature = vi.fn()
     mocks.getState.mockReturnValue({
+      ...createTestStore().getState(),
       settings: null,
       openFiles: [activeFile],
       setLastKnownDiskSignature
diff --git a/src/renderer/src/components/editor/useEditorPanelExternalContentEvents.ts b/src/renderer/src/components/editor/useEditorPanelExternalContentEvents.ts
index a7205c10ca0..6a4f7c75135 100644
--- a/src/renderer/src/components/editor/useEditorPanelExternalContentEvents.ts
+++ b/src/renderer/src/components/editor/useEditorPanelExternalContentEvents.ts
@@ -15,11 +15,7 @@ import { isReloadableSingleFileDiffTab } from './editor-panel-diff-reload'
 import { createEditorWatcherReloadCoalescer } from './editor-watcher-reload-coalescer'
 import { markFileChangedOnDisk } from './editor-changed-on-disk-mark'
 import { hasRecentSelfWrite } from './editor-self-write-registry'
-import {
-  editorModelSiblingTabs,
-  isEditorModelDirty,
-  isWholeEditorState
-} from './editor-save-disk-precondition'
+import { editorModelSiblingTabs, isEditorModelDirty } from './editor-save-disk-precondition'
 
 type EditorViewModeByFile = ReturnType<typeof useAppStore.getState>['editorViewMode']
 
@@ -93,7 +89,7 @@ export function useEditorPanelExternalContentEvents({
         return 'stale'
       }
       // Why: a clean tab of a model another tab is editing shows that buffer; never reload it alone.
-      if (isWholeEditorState(state) && isEditorModelDirty(state, file)) {
+      if (isEditorModelDirty(state, file)) {
         return null
       }
       return isVisibleRef.current && file.id === activeContentFileIdRef.current ? file : 'stale'
@@ -142,8 +138,7 @@ export function useEditorPanelExternalContentEvents({
         // clean tab of a model another tab is editing shows that buffer too.
         if (
           file.isDirty ||
-          (isWholeEditorState(storeState) &&
-            storeState.openFiles.some((tab) => tab.id === file.id) &&
+          (storeState.openFiles.some((tab) => tab.id === file.id) &&
             isEditorModelDirty(storeState, file))
         ) {
           continue
diff --git a/src/renderer/src/components/editor/useEditorPanelVisibilityContentState.test.tsx b/src/renderer/src/components/editor/useEditorPanelVisibilityContentState.test.tsx
index 62c129a7203..7f297c093a1 100644
--- a/src/renderer/src/components/editor/useEditorPanelVisibilityContentState.test.tsx
+++ b/src/renderer/src/components/editor/useEditorPanelVisibilityContentState.test.tsx
@@ -42,6 +42,7 @@ vi.mock('@/store', () => ({ useAppStore: { getState: mocks.getState } }))
 
 import { ORCA_EDITOR_EXTERNAL_FILE_CHANGE_EVENT } from './editor-autosave'
 import { useEditorPanelContentState } from './useEditorPanelContentState'
+import { createTestStore } from '@/store/slices/store-test-helpers'
 
 type Deferred<T> = {
   promise: Promise<T>
@@ -161,6 +162,7 @@ describe('useEditorPanelContentState visibility', () => {
     mocks.readRuntimeFileContent.mockReset()
     mocks.getState.mockReset()
     mocks.getState.mockReturnValue({
+      ...createTestStore().getState(),
       settings: null,
       openFiles: [],
       setLastKnownDiskSignature: vi.fn()
diff --git a/src/renderer/src/hooks/editor-external-watch-disk-verification.ts b/src/renderer/src/hooks/editor-external-watch-disk-verification.ts
index 69fb7933628..ca402b5b88e 100644
--- a/src/renderer/src/hooks/editor-external-watch-disk-verification.ts
+++ b/src/renderer/src/hooks/editor-external-watch-disk-verification.ts
@@ -6,7 +6,7 @@ import {
   notifyEditorExternalFileChange
 } from '@/components/editor/editor-autosave'
 import { markFileChangedOnDisk } from '@/components/editor/editor-changed-on-disk-mark'
-import { getDiskBaselineSignature } from '@/components/editor/diff-content-signature'
+import { getDiskBaselineSignature } from '../../../shared/disk-baseline-signature'
 import {
   clearSelfWrite,
   getRecentSelfWrite,
diff --git a/src/renderer/src/hooks/useEditorExternalWatch-self-move.test.ts b/src/renderer/src/hooks/useEditorExternalWatch-self-move.test.ts
index 48832cfad5b..4de08af22b8 100644
--- a/src/renderer/src/hooks/useEditorExternalWatch-self-move.test.ts
+++ b/src/renderer/src/hooks/useEditorExternalWatch-self-move.test.ts
@@ -20,6 +20,8 @@ import {
 } from './editor-external-watch-event-reconciliation'
 import { verifyLatchedMoveDestinations } from './useEditorExternalWatch'
 import { useAppStore } from '@/store'
+import type { OpenFile } from '@/store/slices/editor'
+import { createTestStore } from '@/store/slices/store-test-helpers'
 import { getOpenFilesForExternalFileChange } from '@/components/editor/editor-autosave'
 import { __clearSelfWriteRegistryForTests } from '@/components/editor/editor-self-write-registry'
 import {
@@ -27,7 +29,7 @@ import {
   beginEditorPathMove,
   settleEditorPathMove
 } from '@/components/editor/editor-path-move-inflight'
-import { getDiskBaselineSignature } from '@/components/editor/diff-content-signature'
+import { getDiskBaselineSignature } from '../../../shared/disk-baseline-signature'
 
 const findTarget = (worktreePath: string, runtimeEnvironmentId: string | null = null) =>
   worktreePath === '/repo'
@@ -46,6 +48,7 @@ describe('self-move source suppression (in-flight)', () => {
     worktreePath: '/repo',
     filePath: '/repo/notes.md',
     relativePath: 'notes.md',
+    language: 'markdown',
     mode: 'edit' as const,
     isDirty: false
   }
@@ -54,9 +57,10 @@ describe('self-move source suppression (in-flight)', () => {
     vi.clearAllMocks()
     vi.useFakeTimers()
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [fileNotes],
       setExternalMutation
-    } as never)
+    })
   })
 
   afterEach(() => {
@@ -97,13 +101,15 @@ describe('self-move source suppression (in-flight)', () => {
       worktreePath: '/repo',
       filePath: '/repo/src/late.md',
       relativePath: 'src/late.md',
+      language: 'markdown',
       mode: 'edit' as const,
       isDirty: true
     }
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [lateTab],
       setExternalMutation
-    } as never)
+    })
     beginEditorPathMove({
       operationId: 'op-dir',
       worktreeId: 'wt-1',
@@ -148,13 +154,13 @@ describe('self-move echo verification (content identity)', () => {
   const baselineSignature = getDiskBaselineSignature(BASELINE_CONTENT)
   const TARGET_PATH = '/repo/subdir/notes.md'
 
-  function movedDirtyTab(overrides: Record<string, unknown> = {}): Record<string, unknown> {
+  function movedDirtyTab(overrides: Partial<OpenFile> = {}): OpenFile {
     return {
       id: 'file-notes',
       worktreeId: 'wt-1',
-      worktreePath: '/repo',
       filePath: TARGET_PATH,
       relativePath: 'subdir/notes.md',
+      language: 'markdown',
       mode: 'edit' as const,
       isDirty: true,
       lastKnownDiskSignature: baselineSignature,
@@ -164,14 +170,15 @@ describe('self-move echo verification (content identity)', () => {
     }
   }
 
-  function mockState(file: Record<string, unknown>): void {
+  function mockState(file: OpenFile): void {
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [file],
       setExternalMutation,
       setPendingLiveDiskVerification,
       clearSelfMoveEcho
-    } as never)
-    vi.mocked(getOpenFilesForExternalFileChange).mockReturnValue([file] as never)
+    })
+    vi.mocked(getOpenFilesForExternalFileChange).mockReturnValue([file])
   }
 
   function payloadFor(): FsChangedPayload {
@@ -293,6 +300,7 @@ describe('verifyLatchedMoveDestinations (proactive, cross-worktree path)', () =>
     filePath: FLOATING_FILE_PATH,
     relativePath: '../notes/readme.md',
     runtimeEnvironmentId: null,
+    language: 'markdown',
     mode: 'edit' as const,
     isDirty: true,
     lastKnownDiskSignature: baseline,
@@ -306,11 +314,12 @@ describe('verifyLatchedMoveDestinations (proactive, cross-worktree path)', () =>
     readFile = vi.fn().mockResolvedValue({ isBinary: false, content: CONTENT })
     vi.stubGlobal('window', { api: { fs: { readFile } } })
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [floatingTab],
       setPendingLiveDiskVerification,
       clearSelfMoveEcho,
       setExternalMutation
-    } as never)
+    })
   })
 
   afterEach(() => {
diff --git a/src/renderer/src/hooks/useEditorExternalWatch-switch-back.test.tsx b/src/renderer/src/hooks/useEditorExternalWatch-switch-back.test.tsx
index abbe04c3fa4..95045b22b1d 100644
--- a/src/renderer/src/hooks/useEditorExternalWatch-switch-back.test.tsx
+++ b/src/renderer/src/hooks/useEditorExternalWatch-switch-back.test.tsx
@@ -48,7 +48,7 @@ vi.mock('@/lib/connection-context', () => ({ getConnectionIdForFile: () => undef
 import { createTestStore } from '@/store/slices/store-test-helpers'
 import { useEditorExternalWatch } from './useEditorExternalWatch'
 import { attachRestoredTabConflictScan } from '@/components/editor/editor-restored-tab-conflict-scan'
-import { getDiskBaselineSignature } from '@/components/editor/diff-content-signature'
+import { getDiskBaselineSignature } from '../../../shared/disk-baseline-signature'
 import {
   isAutosaveSuspendedForFile,
   ORCA_EDITOR_EXTERNAL_FILE_CHANGE_EVENT
diff --git a/src/renderer/src/hooks/useEditorExternalWatch.test.ts b/src/renderer/src/hooks/useEditorExternalWatch.test.ts
index f249f322eef..8ff9b882796 100644
--- a/src/renderer/src/hooks/useEditorExternalWatch.test.ts
+++ b/src/renderer/src/hooks/useEditorExternalWatch.test.ts
@@ -25,6 +25,7 @@ import {
 } from './editor-external-watch-event-reconciliation'
 import { getEditorExternalWatchTargetKey as getWatchedTargetKey } from './editor-external-watch-targets'
 import { useAppStore } from '@/store'
+import { createTestStore } from '@/store/slices/store-test-helpers'
 import {
   getOpenFilesForExternalFileChange,
   notifyEditorExternalFileChange
@@ -101,6 +102,7 @@ describe('createExternalWatchEventHandler tombstone coalescing', () => {
     worktreePath: '/repo',
     filePath: '/repo/notes.md',
     relativePath: 'notes.md',
+    language: 'markdown',
     mode: 'edit' as const,
     isDirty: false
   }
@@ -109,9 +111,10 @@ describe('createExternalWatchEventHandler tombstone coalescing', () => {
     vi.clearAllMocks()
     vi.useFakeTimers()
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [fileNotes],
       setExternalMutation
-    } as never)
+    })
   })
 
   afterEach(() => {
@@ -178,14 +181,16 @@ describe('createExternalWatchEventHandler tombstone coalescing', () => {
       worktreePath: 'C:\\Repo',
       filePath: 'C:\\Repo\\notes.md',
       relativePath: 'notes.md',
+      language: 'markdown',
       mode: 'edit' as const,
       isDirty: false,
       runtimeEnvironmentId: 'env-1'
     }
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [file],
       setExternalMutation
-    } as never)
+    })
     vi.mocked(getOpenFilesForExternalFileChange).mockReturnValue([file] as never)
     const { handleFsChanged, dispose } = createExternalWatchEventHandler(() => ({
       worktreeId: 'wt-win',
@@ -216,14 +221,16 @@ describe('createExternalWatchEventHandler tombstone coalescing', () => {
       worktreePath: '//Server/Share/Repo',
       filePath: '//Server/Share/Repo/notes.md',
       relativePath: 'notes.md',
+      language: 'markdown',
       mode: 'edit' as const,
       isDirty: false,
       runtimeEnvironmentId: 'env-1'
     }
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [file],
       setExternalMutation
-    } as never)
+    })
     vi.mocked(getOpenFilesForExternalFileChange).mockReturnValue([file] as never)
     const { handleFsChanged, dispose } = createExternalWatchEventHandler(() => ({
       worktreeId: 'wt-unc',
@@ -249,9 +256,10 @@ describe('createExternalWatchEventHandler tombstone coalescing', () => {
 
   it('does not drop external edits that arrive inside the self-write TTL', async () => {
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [fileNotes],
       setExternalMutation
-    } as never)
+    })
     vi.mocked(getOpenFilesForExternalFileChange).mockReturnValue([fileNotes] as never)
     const readFile = vi.fn().mockResolvedValue({ content: 'agent edit', isBinary: false })
     vi.stubGlobal('window', { api: { fs: { readFile } } })
@@ -272,9 +280,10 @@ describe('createExternalWatchEventHandler tombstone coalescing', () => {
 
   it('still suppresses the watcher echo from Orca self-writes', async () => {
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [fileNotes],
       setExternalMutation
-    } as never)
+    })
     vi.mocked(getOpenFilesForExternalFileChange).mockReturnValue([fileNotes] as never)
     const readFile = vi.fn().mockResolvedValue({ content: 'orca save', isBinary: false })
     vi.stubGlobal('window', { api: { fs: { readFile } } })
@@ -294,9 +303,10 @@ describe('createExternalWatchEventHandler tombstone coalescing', () => {
       runtimeEnvironmentId: 'env-1'
     }
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [runtimeFile],
       setExternalMutation
-    } as never)
+    })
     vi.mocked(getOpenFilesForExternalFileChange).mockReturnValue([runtimeFile] as never)
     const readFile = vi.fn().mockResolvedValue({ content: 'local save', isBinary: false })
     vi.stubGlobal('window', { api: { fs: { readFile } } })
@@ -323,9 +333,10 @@ describe('createExternalWatchEventHandler tombstone coalescing', () => {
       runtimeEnvironmentId: 'env-1'
     }
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [localFile, runtimeFile],
       setExternalMutation
-    } as never)
+    })
     vi.mocked(getOpenFilesForExternalFileChange).mockImplementation((_files, notification) =>
       notification.runtimeEnvironmentId === 'env-1'
         ? ([runtimeFile] as never)
@@ -359,14 +370,16 @@ describe('createExternalWatchEventHandler tombstone coalescing', () => {
       worktreePath: '/repo',
       filePath: '/repo',
       relativePath: 'Changes',
+      language: 'markdown',
       mode: 'diff' as const,
       diffSource: 'combined-uncommitted' as const,
       isDirty: false
     }
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [combinedDiffTab],
       setExternalMutation
-    } as never)
+    })
     // Why: combined tabs match no single path, so the per-path lookup stays empty.
     vi.mocked(getOpenFilesForExternalFileChange).mockReturnValue([])
     const { handleFsChanged, dispose } = createExternalWatchEventHandler(findTarget)
@@ -394,14 +407,16 @@ describe('createExternalWatchEventHandler tombstone coalescing', () => {
       worktreePath: '/repo',
       filePath: '/repo',
       relativePath: 'Changes',
+      language: 'markdown',
       mode: 'diff' as const,
       diffSource: 'combined-uncommitted' as const,
       isDirty: false
     }
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [dirtyFile, combinedDiffTab],
       setExternalMutation
-    } as never)
+    })
     vi.mocked(getOpenFilesForExternalFileChange).mockReturnValue([dirtyFile] as never)
     const { handleFsChanged, dispose } = createExternalWatchEventHandler(findTarget)
 
@@ -423,9 +438,10 @@ describe('createExternalWatchEventHandler tombstone coalescing', () => {
       isDirty: true
     }
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [dirtyFile],
       setExternalMutation
-    } as never)
+    })
     vi.mocked(getOpenFilesForExternalFileChange).mockReturnValue([dirtyFile] as never)
     const { handleFsChanged, dispose } = createExternalWatchEventHandler(findTarget)
 
@@ -448,14 +464,16 @@ describe('createExternalWatchEventHandler tombstone coalescing', () => {
       worktreePath: '/repo',
       filePath: '/repo/notes.md',
       relativePath: 'notes.md',
+      language: 'markdown',
       mode: 'diff' as const,
       diffSource: 'unstaged' as const,
       isDirty: false
     }
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [dirtyFile, cleanDiffTab],
       setExternalMutation
-    } as never)
+    })
     vi.mocked(getOpenFilesForExternalFileChange).mockReturnValue([dirtyFile, cleanDiffTab] as never)
     const { handleFsChanged, dispose } = createExternalWatchEventHandler(findTarget)
 
@@ -478,9 +496,10 @@ describe('createExternalWatchEventHandler tombstone coalescing', () => {
       isDirty: true
     }
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [dirtyFile],
       setExternalMutation
-    } as never)
+    })
     vi.mocked(getOpenFilesForExternalFileChange).mockReturnValue([dirtyFile] as never)
     const readFile = vi.fn().mockResolvedValue({ content: 'orca save', isBinary: false })
     vi.stubGlobal('window', { api: { fs: { readFile } } })
@@ -500,9 +519,10 @@ describe('createExternalWatchEventHandler tombstone coalescing', () => {
       isDirty: true
     }
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [dirtyFile],
       setExternalMutation
-    } as never)
+    })
     vi.mocked(getOpenFilesForExternalFileChange).mockReturnValue([dirtyFile] as never)
     const readFile = vi.fn().mockResolvedValue({ content: 'agent content', isBinary: false })
     vi.stubGlobal('window', { api: { fs: { readFile } } })
@@ -522,9 +542,10 @@ describe('createExternalWatchEventHandler tombstone coalescing', () => {
       isDirty: true
     }
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [dirtyFile],
       setExternalMutation
-    } as never)
+    })
     vi.mocked(getOpenFilesForExternalFileChange).mockReturnValue([dirtyFile] as never)
     const readFile = vi.fn().mockResolvedValue({ content: 'agent content', isBinary: false })
     vi.stubGlobal('window', { api: { fs: { readFile } } })
@@ -550,9 +571,10 @@ describe('createExternalWatchEventHandler tombstone coalescing', () => {
       isDirty: true
     }
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [dirtyFile],
       setExternalMutation
-    } as never)
+    })
     vi.mocked(getOpenFilesForExternalFileChange).mockReturnValue([dirtyFile] as never)
     let resolveEchoRead: (value: { content: string; isBinary: boolean }) => void = () => {}
     const readFile = vi
@@ -587,14 +609,16 @@ describe('createExternalWatchEventHandler tombstone coalescing', () => {
       worktreePath: '/repo',
       filePath: '/repo/notes.md',
       relativePath: 'notes.md',
+      language: 'markdown',
       mode: 'diff' as const,
       diffSource: 'unstaged' as const,
       isDirty: true
     }
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [dirtyDiffTab],
       setExternalMutation
-    } as never)
+    })
     vi.mocked(getOpenFilesForExternalFileChange).mockReturnValue([dirtyDiffTab] as never)
     const { handleFsChanged, dispose } = createExternalWatchEventHandler(findTarget)
 
@@ -613,9 +637,10 @@ describe('createExternalWatchEventHandler tombstone coalescing', () => {
       externalMutation: 'changed' as const
     }
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [dirtyChangedFile],
       setExternalMutation
-    } as never)
+    })
     vi.mocked(getOpenFilesForExternalFileChange).mockReturnValue([dirtyChangedFile] as never)
     const { handleFsChanged, dispose } = createExternalWatchEventHandler(findTarget)
 
@@ -633,14 +658,16 @@ describe('createExternalWatchEventHandler tombstone coalescing', () => {
       worktreePath: '/repo',
       filePath: '/repo',
       relativePath: 'Branch Changes',
+      language: 'markdown',
       mode: 'diff' as const,
       diffSource: 'combined-branch' as const,
       isDirty: false
     }
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [branchDiffTab],
       setExternalMutation
-    } as never)
+    })
     vi.mocked(getOpenFilesForExternalFileChange).mockReturnValue([])
     const { handleFsChanged, dispose } = createExternalWatchEventHandler(findTarget)
 
@@ -659,9 +686,10 @@ describe('createExternalWatchEventHandler tombstone coalescing', () => {
       runtimeEnvironmentId: 'env-1'
     }
     vi.mocked(useAppStore.getState).mockReturnValue({
+      ...createTestStore().getState(),
       openFiles: [localFile, runtimeFile],
       setExternalMutation
-    } as never)
+    })
     const { handleFsChanged, dispose } = createExternalWatchEventHandler(findTarget)
 
     handleFsChanged(payload([{ kind: 'delete', absolutePath: '/repo/notes.md' }]), 'env-1')
diff --git a/src/renderer/src/lib/execute-open-editor-path-move.test.ts b/src/renderer/src/lib/execute-open-editor-path-move.test.ts
index cf3c1c433db..b85e1e44868 100644
--- a/src/renderer/src/lib/execute-open-editor-path-move.test.ts
+++ b/src/renderer/src/lib/execute-open-editor-path-move.test.ts
@@ -15,7 +15,7 @@ vi.mock('@/components/editor/editor-autosave', async (importOriginal) => {
 import { useAppStore } from '@/store'
 import { executeOpenEditorPathMove } from './execute-open-editor-path-move'
 import { __activeEditorPathMoveCountForTests } from '@/components/editor/editor-path-move-inflight'
-import { getDiskBaselineSignature } from '@/components/editor/diff-content-signature'
+import { getDiskBaselineSignature } from '../../../shared/disk-baseline-signature'
 import { buildEditorExternalWatchEventHandler as createExternalWatchEventHandler } from '@/hooks/editor-external-watch-event-reconciliation'
 
 const CONTEXT = {
diff --git a/src/renderer/src/store/slices/editor/tabs/untitled-file-cleanup.ts b/src/renderer/src/store/slices/editor/tabs/untitled-file-cleanup.ts
index 4ac81fab497..abf08ba2cb7 100644
--- a/src/renderer/src/store/slices/editor/tabs/untitled-file-cleanup.ts
+++ b/src/renderer/src/store/slices/editor/tabs/untitled-file-cleanup.ts
@@ -3,7 +3,7 @@ import type { OpenFile } from '../types/open-file'
 import { mayShareEditorBackingFile } from '../file-ids/editor-file-ids'
 import { findWorktreeById } from '../../worktree-helpers'
 import { getEditorFileOperationContext } from '@/lib/editor-file-operation-owner'
-import { getDiskBaselineSignature } from '@/components/editor/diff-content-signature'
+import { getDiskBaselineSignature } from '../../../../../../shared/disk-baseline-signature'
 import {
   deleteRuntimePath,
   deleteRuntimeRelativePath