perf(native-chat): batch background reply status publications (#42550)

* perf(native-chat): reuse deterministic session pane identity

* perf(native-chat): batch streaming status facts between transitions

* perf(native-chat): keep pending prose off focus reconciliation

* test(native-chat): model live panes in switch regression fixture

config/scripts/static-analysis/ratchets/renderer-state/check-tab-map-seam-ratchet.mjs

@@ -49,6 +49,9 @@ export const CONSUMERS = new Map([
         'ownerInputChanged',
         'ownerInputs',
         'createStructuredSessionMembership',
+        'createStructuredSessionStatusBurst',
+        'sameCapturedInput',
+        'sameStatusInput',
         'sameSemanticTab'
       ])
     }

src/renderer/src/components/native-chat/session/status/StructuredAgentSessionStatusBridge.tsx

@@ -1,3 +1,4 @@
+import { createStructuredSessionStatusBurst } from './structured-agent-session-status-burst'
 import { useEffect } from 'react'
 import { projectStatus } from './structured-agent-session-status-projection'
 import { getStructuredAgentSessionLaunchLifecycle } from '@/lib/agent-session/launch/structured-agent-session-launch-registry'
@@ -27,32 +28,11 @@ import {
   type HostGroup,
   type Member,
   type ProjectionInput,
-  sameSemanticTab
+  sameSemanticTab,
+  sameCapturedInput,
+  sameStatusInput
 } from './structured-agent-session-status-membership'
 
-/** Unchanged feed facts for an unchanged tab cannot change its projection or companions. */
-function sameCapturedInput(previous: ProjectionInput | undefined, next: ProjectionInput): boolean {
-  return (
-    previous !== undefined &&
-    sameSemanticTab(previous.tab, next.tab) &&
-    previous.summary === next.summary &&
-    previous.observation === next.observation &&
-    previous.failedAt === next.failedAt &&
-    previous.sleptAt === next.sleptAt &&
-    previous.directory === next.directory
-  )
-}
-
-function sameStatusInput(previous: ProjectionInput | undefined, next: ProjectionInput): boolean {
-  return (
-    previous !== undefined &&
-    sameSemanticTab(previous.tab, next.tab) &&
-    previous.summary === next.summary &&
-    previous.observation === next.observation &&
-    previous.failedAt === next.failedAt
-  )
-}
-
 function installStatusProjection(): () => void {
   const membership = createStructuredSessionMembership()
   const { members, membersByTabId, legacy } = membership
@@ -192,6 +172,19 @@ function installStatusProjection(): () => void {
       membership.settle(input.member)
     }
   }
+  const publish = (inputs: ProjectionInput[]): void => {
+    try {
+      project(inputs)
+    } catch (error) {
+      for (const input of inputs) {
+        if (current(input)) {
+          membership.owe(input.member)
+        }
+      }
+      throw error
+    }
+  }
+  const burst = createStructuredSessionStatusBurst(publish, enqueue)
   const activateGroups = (): void => {
     for (const [hostKey, group] of groups) {
       if (groups.get(hostKey) === group && group.members.size && !group.release) {
@@ -223,17 +216,25 @@ function installStatusProjection(): () => void {
         directory: member.hostKey === 'local' ? summary?.launchDirectory : undefined
       }
       // Launch ticks and full host ticks carry every member; skip the unchanged ones.
-      if (!sameCapturedInput(member.captured, input)) {
+      if (!sameCapturedInput(burst.peek(member) ?? member.captured, input)) {
         inputs.push(input)
-        membership.owe(member)
       } else {
         membership.settle(member)
       }
     }
     enqueue(
       () => {
-        activateGroups()
-        project(inputs)
+        try {
+          activateGroups()
+          burst.add(inputs.filter(current))
+        } catch (error) {
+          for (const input of inputs) {
+            if (current(input)) {
+              membership.owe(input.member)
+            }
+          }
+          throw error
+        }
       },
       inputs.map(({ member }) => ({ host: member.hostKey, paneKey: member.paneKey }))
     )
@@ -280,7 +281,11 @@ function installStatusProjection(): () => void {
   }
   const place = (state: AppState, tab: StructuredTab, paneKey: string, changed: Set<Member>) => {
     const { hostKey, group } = groupFor(state, tab)
+    const old = members.get(paneKey)
     const member = membership.place(tab, paneKey, hostKey, group)
+    if (old && members.get(paneKey) !== old) {
+      burst.forget(old)
+    }
     if (member) {
       changed.add(member)
     }
@@ -317,6 +322,7 @@ function installStatusProjection(): () => void {
       }
     }
     for (const member of retiring) {
+      burst.forget(member)
       membership.detach(member)
       retired.add(member)
     }
@@ -373,6 +379,7 @@ function installStatusProjection(): () => void {
   boundary(() => reconcile(false))
   return () => {
     disposed = true
+    burst.dispose()
     unsubscribeApp()
     unsubscribeLaunch()
     for (const group of groups.values()) {

src/renderer/src/components/native-chat/session/status/structured-agent-session-status-burst.ts

@@ -0,0 +1,96 @@
+import { structuralValuesEqualIgnoringUndefined } from '../../../../../../shared/structural-value-equality'
+import {
+  sameSemanticTab,
+  type Member,
+  type ProjectionInput
+} from './structured-agent-session-status-membership'
+
+const STREAMING_BURST_WINDOW_MS = 33
+
+function streamingOnly(previous: ProjectionInput | undefined, next: ProjectionInput): boolean {
+  if (
+    !previous ||
+    previous.summary?.status !== 'working' ||
+    next.summary?.status !== 'working' ||
+    !sameSemanticTab(previous.tab, next.tab) ||
+    previous.observation !== next.observation ||
+    previous.failedAt !== next.failedAt ||
+    previous.sleptAt !== next.sleptAt ||
+    previous.directory !== next.directory
+  ) {
+    return false
+  }
+  const {
+    lastAssistantMessage: _previousText,
+    updatedAt: _previousTime,
+    ...before
+  } = previous.summary
+  const { lastAssistantMessage: _nextText, updatedAt: _nextTime, ...after } = next.summary
+  return structuralValuesEqualIgnoringUndefined(before, after)
+}
+
+/** Retain only the latest prose tick per member; publish every semantic transition synchronously. */
+export function createStructuredSessionStatusBurst(
+  publish: (inputs: ProjectionInput[]) => void,
+  enqueue: (operation: () => void) => void
+) {
+  const pending = new Map<Member, ProjectionInput>()
+  let timer: ReturnType<typeof setTimeout> | null = null
+  let lastPublishedAt = 0
+  let disposed = false
+  const cancelTimer = (): void => {
+    if (timer !== null) {
+      clearTimeout(timer)
+      timer = null
+    }
+  }
+  const apply = (inputs: ProjectionInput[]): void => {
+    lastPublishedAt = Date.now()
+    publish(inputs)
+  }
+  const flush = (): void => {
+    cancelTimer()
+    const inputs = [...pending.values()]
+    pending.clear()
+    if (!disposed && inputs.length) {
+      apply(inputs)
+    }
+  }
+  return {
+    flush,
+    peek: (member: Member): ProjectionInput | undefined => pending.get(member),
+    add: (inputs: ProjectionInput[]): void => {
+      if (disposed) {
+        return
+      }
+      if (!inputs.length) {
+        publish(inputs)
+        return
+      }
+      if (inputs.some((input) => !streamingOnly(input.member.captured, input))) {
+        flush()
+        apply(inputs)
+        return
+      }
+      if (timer === null && Date.now() - lastPublishedAt >= STREAMING_BURST_WINDOW_MS) {
+        apply(inputs)
+        return
+      }
+      for (const input of inputs) {
+        pending.set(input.member, input)
+      }
+      timer ??= setTimeout(() => enqueue(flush), STREAMING_BURST_WINDOW_MS)
+    },
+    forget: (member: Member): void => {
+      pending.delete(member)
+      if (!pending.size) {
+        cancelTimer()
+      }
+    },
+    dispose: (): void => {
+      disposed = true
+      cancelTimer()
+      pending.clear()
+    }
+  }
+}

src/renderer/src/components/native-chat/session/status/structured-agent-session-status-membership.ts

@@ -45,6 +45,35 @@ export function sameSemanticTab(previous: StructuredTab, next: StructuredTab): b
   )
 }
 
+/** Unchanged feed facts for an unchanged tab cannot change its projection or companions. */
+export function sameCapturedInput(
+  previous: ProjectionInput | undefined,
+  next: ProjectionInput
+): boolean {
+  return (
+    previous !== undefined &&
+    sameSemanticTab(previous.tab, next.tab) &&
+    previous.summary === next.summary &&
+    previous.observation === next.observation &&
+    previous.failedAt === next.failedAt &&
+    previous.sleptAt === next.sleptAt &&
+    previous.directory === next.directory
+  )
+}
+
+export function sameStatusInput(
+  previous: ProjectionInput | undefined,
+  next: ProjectionInput
+): boolean {
+  return (
+    previous !== undefined &&
+    sameSemanticTab(previous.tab, next.tab) &&
+    previous.summary === next.summary &&
+    previous.observation === next.observation &&
+    previous.failedAt === next.failedAt
+  )
+}
+
 /** Which chat tabs the status bridge projects, updated per changed tab rather than rebuilt. */
 export function createStructuredSessionMembership() {
   const members = new Map<string, Member>()