fix(mobile): unsubscribe session tabs by request on the direct connection (#22943)

* fix(mobile): unsubscribe session tabs by request on the direct connection

* fix(mobile): hold a direct session tabs unsubscribe until the first snapshot

The desktop registers a tab-list stream only as it emits the first snapshot. A direct
unsubscribe sent before that found nothing, and with per-request addressing no later
worktree-wide sweep collects the late stream, so it kept its desktop listener until the
socket closed. Hold the unsubscribe until the snapshot arrives, as the relay connection does.

* test(mobile): cover a held session tabs unsubscribe whose subscribe fails

* fix(mobile): keep the session tabs hold within the registry line budget after merging main

Move the pre-snapshot hold into the session tabs stream module, note that only older hosts need it, and give the unsubscribe test the real registration version now that a worktree-wide unsubscribe spares later streams.

src/main/runtime/rpc/methods/session-tabs-unsubscribe.test.ts

@@ -1,5 +1,6 @@
 import { describe, expect, it, vi } from 'vitest'
 import type { OrcaRuntimeService } from '../../orca-runtime'
+import { RuntimeSubscriptionRegistry } from '../../runtime-subscription-registry'
 import { RpcDispatcher } from '../dispatcher'
 import { SESSION_TAB_METHODS } from './session-tabs'
 
@@ -61,11 +62,61 @@ describe('session tab unsubscribe RPC methods', () => {
     expect(cleanupSubscription).toHaveBeenCalledWith('session.tabs:conn-1:*:sub-all-1')
     expect(cleanupSubscriptionsByPrefix).not.toHaveBeenCalled()
   })
+
+  it('ends only the named stream when a newer one watches the same worktree', async () => {
+    const { dispatcher, ends } = await subscribeTwiceToOneWorktree()
+
+    await dispatcher.dispatchStreaming(
+      request('session.tabs.unsubscribe', { worktree: 'id:wt-1', subscriptionId: 'sub-old' }),
+      vi.fn(),
+      { connectionId: 'conn-1' }
+    )
+
+    await vi.waitFor(() => expect(ends['sub-old']).toBe(1))
+    expect(ends['sub-new']).toBe(0)
+  })
+
+  it('ends every stream for the worktree when the unsubscribe names no request', async () => {
+    const { dispatcher, ends } = await subscribeTwiceToOneWorktree()
+
+    await dispatcher.dispatchStreaming(
+      request('session.tabs.unsubscribe', { worktree: 'id:wt-1' }),
+      vi.fn(),
+      { connectionId: 'conn-1' }
+    )
+
+    await vi.waitFor(() => expect(ends).toEqual({ 'sub-old': 1, 'sub-new': 1 }))
+  })
 })
 
+async function subscribeTwiceToOneWorktree() {
+  const registry = new RuntimeSubscriptionRegistry()
+  // oxlint-disable-next-line typescript/consistent-type-assertions -- SAFETY: Partial runtime backed by the real subscription registry; it supplies every member session.tabs subscribe/unsubscribe call.
+  const runtime = {
+    ...runtimeWithCleanup(registry.cleanup.bind(registry), registry.cleanupByPrefix.bind(registry)),
+    registerSubscriptionCleanup: registry.register.bind(registry),
+    getSubscriptionRegistrationVersion: registry.getRegistrationVersion.bind(registry),
+    onMobileSessionTabsChanged: () => () => {}
+  } as unknown as OrcaRuntimeService
+  const dispatcher = new RpcDispatcher({ runtime, methods: SESSION_TAB_METHODS })
+  const ends: Record<string, number> = { 'sub-old': 0, 'sub-new': 0 }
+  for (const id of ['sub-old', 'sub-new']) {
+    await dispatcher.dispatchStreaming(
+      { ...request('session.tabs.subscribe', { worktree: 'id:wt-1' }), id },
+      (message) => {
+        if (JSON.parse(message).result?.type === 'end') {
+          ends[id]! += 1
+        }
+      },
+      { connectionId: 'conn-1' }
+    )
+  }
+  return { dispatcher, ends }
+}
+
 function runtimeWithCleanup(
-  cleanupSubscription: ReturnType<typeof vi.fn>,
-  cleanupSubscriptionsByPrefix = vi.fn()
+  cleanupSubscription: (id: string) => void,
+  cleanupSubscriptionsByPrefix: (prefix: string, throughVersion?: number) => void = vi.fn()
 ): OrcaRuntimeService {
   // oxlint-disable-next-line typescript/consistent-type-assertions -- SAFETY: the unsubscribe methods reach only these members; a missing one throws and fails the test.
   return {