perf: overhaul session loading, caching, and runtime isolation (#2360)

Improve OpenChamber responsiveness under large session workloads while fixing
cache, synchronization, and persistence correctness across runtimes, projects,
directories, and worktrees.

- prioritize selected and visible sessions during bootstrap and defer
  non-critical enrichment work
- reduce redundant message loading, event processing, store publication, and
  hidden sidebar work
- prevent stale session and message requests from overwriting newer
  authoritative state
- preserve existing data when authoritative fetches fail instead of treating
  failures as successful empty responses
- scope session materialization, messages, drafts, queues, todos, pins,
  permissions, folders, tabs, Git state, and pull request data by runtime and
  directory identity
- harden runtime switching, reconnect, cleanup, mutation reconciliation, and
  persisted-state ordering
- preserve live subagent Task linkage when metadata arrives after an older
  message request or while streaming parts are suspended
- coalesce overlapping tail refreshes without losing newer refresh demand
- improve cold-session loading by moving deferrable work out of the critical
  bootstrap path
- isolate URL authentication, mobile credentials, native secrets, and other
  runtime-owned state across endpoint changes
- bound long-lived caches and remove avoidable allocations from event and
  rendering hot paths
- limit virtualization to archive collections where it improves rendering
  without disrupting active sidebar layout
- stabilize session folders, pin ordering, expanded state, and persisted
  sidebar behavior
- open skill files through the same secure editor and outside-workspace grant
  flow used by file navigation, including worktree sessions
- expand regression coverage for stale completions, runtime collisions,
  reconnect behavior, persistence races, authoritative empty results, and
  subagent refresh ordering
- document the updated synchronization, cache ownership, performance, and
  runtime-isolation invariants

packages/ui/src/stores/useFileSearchStore.test.ts

@@ -7,6 +7,7 @@ type Deferred<T> = {
 };
 
 const searchRequests: Array<Deferred<Array<{ path: string }>>> = [];
+let runtimeKey = 'runtime-a';
 
 const createDeferred = <T>(): Deferred<T> => {
   let resolve!: (value: T) => void;
@@ -29,12 +30,14 @@ mock.module('@/lib/opencode/client', () => ({
     searchFiles: searchFilesMock,
   },
 }));
+mock.module('@/lib/runtime-switch', () => ({ getRuntimeKey: () => runtimeKey }));
 
 const { useFileSearchStore } = await import('./useFileSearchStore');
 
 describe('useFileSearchStore', () => {
   beforeEach(() => {
     searchRequests.length = 0;
+    runtimeKey = 'runtime-a';
     useFileSearchStore.setState({
       cache: {},
       cacheKeys: [],
@@ -101,4 +104,20 @@ describe('useFileSearchStore', () => {
     searchRequests[1].resolve([{ path: 'second.ts' }]);
     expect(await secondPromise).toEqual([{ path: 'second.ts' }]);
   });
+
+  test('isolates cache and in-flight ownership by runtime', async () => {
+    const firstPromise = useFileSearchStore.getState().searchFiles('/project', 'foo');
+    runtimeKey = 'runtime-b';
+    const secondPromise = useFileSearchStore.getState().searchFiles('/project', 'foo');
+    expect(searchRequests).toHaveLength(2);
+
+    searchRequests[1].resolve([{ path: 'runtime-b.ts' }]);
+    expect(await secondPromise).toEqual([{ path: 'runtime-b.ts' }]);
+    searchRequests[0].resolve([{ path: 'runtime-a.ts' }]);
+    await firstPromise;
+
+    runtimeKey = 'runtime-b';
+    expect(await useFileSearchStore.getState().searchFiles('/project', 'foo')).toEqual([{ path: 'runtime-b.ts' }]);
+    expect(searchRequests).toHaveLength(2);
+  });
 });