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/chat/message/parts/ProgressiveGroup.tsx

@@ -623,7 +623,7 @@ const StaticToolRowInner: React.FC<{
         return entries;
     }, [activities, currentDirectory, isReadGroup]);
 
-    const handleReadFileClick = React.useCallback((filePath: string, offset?: number) => {
+    const handleFileClick = React.useCallback((filePath: string, offset?: number) => {
         const absolutePath = toAbsoluteFilePath(currentDirectory, filePath);
         if (!absolutePath) {
             return;
@@ -656,14 +656,6 @@ const StaticToolRowInner: React.FC<{
         uiStore.openContextFile(contextDirectory, absolutePath);
     }, [currentDirectory, runtime]);
 
-    const handleSkillClick = React.useCallback((skillPath: string) => {
-        if (!skillPath) {
-            return;
-        }
-        const uiStore = useUIStore.getState();
-        uiStore.openContextFile(currentDirectory || getDirectoryForFilePath('', skillPath), skillPath);
-    }, [currentDirectory]);
-
     const normalizedToolName = toolName.toLowerCase();
     const isSearchGroup = normalizedToolName === 'grep'
         || normalizedToolName === 'search'
@@ -699,7 +691,7 @@ const StaticToolRowInner: React.FC<{
                         onClick={(event) => {
                             event.preventDefault();
                             event.stopPropagation();
-                            handleReadFileClick(entry.path, entry.offset);
+                            handleFileClick(entry.path, entry.offset);
                         }}
                         className={cn('inline-flex !min-h-0 items-center justify-start gap-1 min-w-0 flex-1 text-left hover:opacity-90', TOOL_ROW_DESCRIPTION_CLASS)}
                         style={{ color: 'var(--tools-description)' }}
@@ -751,7 +743,7 @@ const StaticToolRowInner: React.FC<{
                         onClick={(event) => {
                             event.preventDefault();
                             event.stopPropagation();
-                            handleSkillClick(entry.path);
+                            handleFileClick(entry.path);
                         }}
                         className={cn('!min-h-0 min-w-0 flex-1 truncate whitespace-nowrap text-left hover:opacity-90', TOOL_ROW_DESCRIPTION_CLASS)}
                         style={{ color: 'var(--tools-description)' }}