fix(sidebar): key parent-expansion per render context (#1302)

The same session can appear in two render contexts at once — most
visibly under "Recent" and under its project's root group. Expansion
state was keyed by bare session id, so toggling the chevron in one
context flipped it in the other; the user clicked one row and a
duplicate elsewhere expanded/collapsed in sync.

Switch the expansion set to composite keys of the form
`<renderContext>:<active|archived>:<sessionId>`. SessionNodeItem
already computes this exact shape for its menu instance key
(menuInstanceKey); reuse it as expansionKey so the two render-time
instances of one session keep independent expand state. Updated:

- isExpanded reads `expandedParents.has(expansionKey)`.
- Chevron click / Enter / Space pass `expansionKey` to toggleParent
  instead of session.id.
- The memo-equality check compares the same composite key on both
  sides so it correctly re-renders when only one context's state
  changes.
- toggleParent's parameter is renamed `expansionKey` to reflect the
  new shape; the implementation is unchanged.
- The auto-expand-parent-on-subagent-navigation effect doesn't know
  which context the user will look at the parent in, so it fans the
  parentID out to all four (project|recent) × (active|archived)
  combinations.

Storage is bumped to `oc.sessions.expandedParents.v2`. Existing v1
data (bare session ids) is one-shot migrated by fanning each id
across all four contexts and rewritten under the v2 key; the v1 key
is then removed so a downgrade-then-reupgrade doesn't re-migrate.

Co-authored-by: vhqtvn <8930337+vhqtvn@users.noreply.github.com>

packages/ui/src/components/session/sidebar/hooks/useSidebarPersistence.ts

@@ -6,10 +6,16 @@ import { useProjectsStore } from '@/stores/useProjectsStore';
 type SafeStorageLike = {
   getItem: (key: string) => string | null;
   setItem: (key: string, value: string) => void;
+  removeItem?: (key: string) => void;
 };
 
 type Keys = {
   sessionExpanded: string;
+  // v1 key, still on disk for users upgrading from pre-per-context expansion.
+  // When present, its bare-session-id entries are fanned out to all four
+  // (project|recent) × (active|archived) context combinations and rewritten
+  // under `sessionExpanded`. After migration the v1 key is removed.
+  sessionExpandedLegacy: string;
   projectCollapse: string;
   sessionPinned: string;
   groupOrder: string;
@@ -17,6 +23,13 @@ type Keys = {
   groupCollapse: string;
 };
 
+const LEGACY_EXPANSION_CONTEXT_PREFIXES = [
+  'project:active:',
+  'project:archived:',
+  'recent:active:',
+  'recent:archived:',
+];
+
 type Args = {
   isVSCode: boolean;
   hasLoadedGlobalSessions: boolean;
@@ -101,6 +114,28 @@ export const useSidebarPersistence = (args: Args) => {
         if (Array.isArray(parsed)) {
           setExpandedParents(new Set(parsed.filter((item) => typeof item === 'string')));
         }
+      } else {
+        // No v2 data — migrate from v1 (bare session ids) if present.
+        const legacyRaw = safeStorage.getItem(keys.sessionExpandedLegacy);
+        if (legacyRaw) {
+          try {
+            const parsedLegacy = JSON.parse(legacyRaw);
+            if (Array.isArray(parsedLegacy)) {
+              const migrated = new Set<string>();
+              parsedLegacy.forEach((item) => {
+                if (typeof item !== 'string' || item.length === 0) return;
+                LEGACY_EXPANSION_CONTEXT_PREFIXES.forEach((prefix) => migrated.add(`${prefix}${item}`));
+              });
+              if (migrated.size > 0) {
+                setExpandedParents(migrated);
+                try { safeStorage.setItem(keys.sessionExpanded, JSON.stringify(Array.from(migrated))); } catch { /* ignored */ }
+              }
+            }
+          } catch {
+            // legacy data was malformed; ignore and let it expire
+          }
+          try { safeStorage.removeItem?.(keys.sessionExpandedLegacy); } catch { /* ignored */ }
+        }
       }
       const storedProjects = safeStorage.getItem(keys.projectCollapse);
       if (storedProjects) {
@@ -112,7 +147,7 @@ export const useSidebarPersistence = (args: Args) => {
     } catch {
       // ignored
     }
-  }, [keys.projectCollapse, keys.sessionExpanded, safeStorage, setCollapsedProjects, setExpandedParents]);
+  }, [keys.projectCollapse, keys.sessionExpanded, keys.sessionExpandedLegacy, safeStorage, setCollapsedProjects, setExpandedParents]);
 
   React.useEffect(() => {
     if (!hasLoadedGlobalSessions) {