fix: align frontend API paths with backend endpoints

- handoffs: /handoffs/queue → /ai-sessions/queue, claim needs sessionId
- resolutions: /resolution-outputs → /outputs
- branches: /status suffix removed from PATCH path
- Add SessionQueuePage route at /queue

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/api/branches.ts

@@ -32,8 +32,8 @@ export const branchesApi = {
     reason?: string
   ): Promise<void> {
     await apiClient.patch(
-      `/ai-sessions/${sessionId}/branches/${branchId}/status`,
-      { status, reason }
+      `/ai-sessions/${sessionId}/branches/${branchId}`,
+      { status, status_reason: reason }
     )
   },