fix(orchestrator): complete remaining high/medium priority fixes

Backend (orchestrator-routes.ts):
- Added broadcastExecutionStatusMessage helper for specific message types
- Added EXECUTION_PAUSED, EXECUTION_RESUMED, EXECUTION_STOPPED broadcasts
- Added CLI_SESSION_UNLOCKED broadcast on execution completion/failure
- Added sessionKey to ExecutionState interface for tracking
- Added totalSteps to EXECUTION_STARTED WebSocket message

Frontend (executionMonitorStore.ts):
- Added EXECUTION_FAILED message type handling
- Added totalSteps extraction from EXECUTION_STARTED payload
- Implemented pauseExecution, resumeExecution, stopExecution API calls
- Replaced TODO console.log with actual fetch API calls

Frontend (useWebSocket.ts):
- Added import for executionMonitorStore
- Added EXECUTION_* message routing to executionMonitorStore

ccw/frontend/src/hooks/useWebSocket.ts

@@ -13,6 +13,10 @@ import {
   handleSessionLockedMessage,
   handleSessionUnlockedMessage,
 } from '@/stores/sessionManagerStore';
+import {
+  useExecutionMonitorStore,
+  type ExecutionWSMessage,
+} from '@/stores/executionMonitorStore';
 import {
   OrchestratorMessageSchema,
   type OrchestratorWebSocketMessage,
@@ -330,6 +334,13 @@ export function useWebSocket(options: UseWebSocketOptions = {}): UseWebSocketRet
           return;
         }
 
+        // Handle EXECUTION messages (from orchestrator execution-in-session)
+        if (data.type?.startsWith('EXECUTION_')) {
+          const handleExecutionMessage = useExecutionMonitorStore.getState().handleExecutionMessage;
+          handleExecutionMessage(data as ExecutionWSMessage);
+          return;
+        }
+
         // Handle A2UI surface messages
         if (data.type === 'a2ui-surface') {
           const parsed = SurfaceUpdateSchema.safeParse(data.payload);