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/components/session/sidebar/utils.test.ts

@@ -1,5 +1,9 @@
 import { describe, expect, test } from 'bun:test';
-import { isPathWithinProject } from './utils';
+import {
+  isPathWithinProject,
+  selectExpandedParentKeysForContext,
+  toggleExpandedParentKey,
+} from './utils';
 
 describe('isPathWithinProject', () => {
   test('matches child directories for root projects', () => {
@@ -26,3 +30,48 @@ describe('isPathWithinProject', () => {
     expect(isPathWithinProject('/workspace/app/sub/dir', '/workspace/app')).toBe(true);
   });
 });
+
+describe('selectExpandedParentKeysForContext', () => {
+  test('keeps project and recent expansion state isolated', () => {
+    const expanded = new Set([
+      'project:active:parent-a',
+      'project:archived:parent-b',
+      'recent:active:parent-a',
+    ]);
+
+    expect(selectExpandedParentKeysForContext(new Set(), expanded, 'project')).toEqual(new Set([
+      'project:active:parent-a',
+      'project:archived:parent-b',
+    ]));
+    expect(selectExpandedParentKeysForContext(new Set(), expanded, 'recent')).toEqual(new Set([
+      'recent:active:parent-a',
+    ]));
+  });
+
+  test('preserves a context projection when only another context changes', () => {
+    const recent = new Set(['recent:active:parent-a']);
+    const expanded = new Set(['recent:active:parent-a', 'project:active:parent-a']);
+
+    expect(selectExpandedParentKeysForContext(recent, expanded, 'recent')).toBe(recent);
+  });
+});
+
+describe('parent expansion state', () => {
+  const recentKey = 'recent:active:parent-a';
+  const projectKey = 'project:active:parent-a';
+
+  test('manually expands and collapses a parent', () => {
+    const expanded = toggleExpandedParentKey(new Set(), recentKey);
+    expect(expanded).toEqual(new Set([recentKey]));
+    expect(toggleExpandedParentKey(expanded, recentKey)).toEqual(new Set());
+  });
+
+  test('does not change the other render context', () => {
+    const recentExpanded = new Set([recentKey]);
+    const bothExpanded = toggleExpandedParentKey(recentExpanded, projectKey);
+    const projectCollapsed = toggleExpandedParentKey(bothExpanded, projectKey);
+
+    expect(selectExpandedParentKeysForContext(new Set(), bothExpanded, 'recent')).toEqual(new Set([recentKey]));
+    expect(selectExpandedParentKeysForContext(new Set(), projectCollapsed, 'recent')).toEqual(new Set([recentKey]));
+  });
+});