chat: rename sessions in Claude's store + delete confirm

Rename appends a {"type":"summary",...} entry to the session's JSONL transcript
(Claude's own format, so the title lives in .claude); the reader takes the last
summary as the title, without a timestamp so it doesn't reorder the list.
PATCH /chat/sessions/:id/title backs it. The list gets inline rename (pencil ->
edit in place) and a two-step delete confirm so a stray click can't nuke a
transcript. Rename verified against a synthetic store.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/workspaces/state/src/useClaudeSessions.ts

@@ -47,5 +47,13 @@ export function useClaudeSessions() {
     [client, invalidate],
   );
 
-  return { sessions: data?.sessions ?? [], isLoading, refetch, loadSession, deleteSession, invalidate };
+  const renameSession = useCallback(
+    async (id: string, title: string) => {
+      await client.patch(`/chat/sessions/${id}/title`, { title });
+      invalidate();
+    },
+    [client, invalidate],
+  );
+
+  return { sessions: data?.sessions ?? [], isLoading, refetch, loadSession, deleteSession, renameSession, invalidate };
 }