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/SidebarProjectsList.tsx

@@ -18,6 +18,7 @@ import { formatProjectLabel } from './utils';
 import { useI18n } from '@/lib/i18n';
 import type { MainTab } from '@/stores/useUIStore';
 import type { ProjectSortOrder } from '@/stores/useSessionDisplayStore';
+import { streamPerfCount } from '@/stores/utils/streamDebug';
 
 type ProjectSection = {
   project: {
@@ -78,7 +79,8 @@ type Props = {
   isInlineEditing: boolean;
 };
 
-export function SidebarProjectsList(props: Props): React.ReactNode {
+function SidebarProjectsListComponent(props: Props): React.ReactNode {
+  streamPerfCount('ui.sidebar_projects_list.render');
   const { t } = useI18n();
   const projectSensors = useSensors(
     useSensor(PointerSensor, { activationConstraint: { distance: 8 } }),
@@ -311,3 +313,5 @@ export function SidebarProjectsList(props: Props): React.ReactNode {
     </ScrollableOverlay>
   );
 }
+
+export const SidebarProjectsList = React.memo(SidebarProjectsListComponent);