feat(orchestrator): redesign orchestrator page as template editor with terminal execution

Phase 1: Orchestrator Simplification
- Remove ExecutionMonitor from OrchestratorPage
- Replace "Run Workflow" button with "Send to Terminal" button
- Update i18n texts for template editor context

Phase 2: Session Lock Mechanism
- Add 'locked' status to TerminalStatus type
- Extend TerminalMeta with isLocked, lockReason, lockedByExecutionId, lockedAt
- Implement lockSession/unlockSession in sessionManagerStore
- Create SessionLockConfirmDialog component for input interception

Phase 3: Execution Monitor Panel
- Create executionMonitorStore for execution state management
- Create ExecutionMonitorPanel component with step progress display
- Add execution panel to DashboardToolbar and TerminalDashboardPage
- Support WebSocket message handling for execution updates

Phase 4: Execution Bridge
- Add POST /api/orchestrator/flows/:id/execute-in-session endpoint
- Create useExecuteFlowInSession hook for frontend API calls
- Broadcast EXECUTION_STARTED and CLI_SESSION_LOCKED WebSocket messages
- Lock session when execution starts, unlock on completion

ccw/frontend/src/locales/en/orchestrator.json

@@ -1,6 +1,6 @@
 {
-  "title": "Orchestrator",
-  "description": "Manage and execute workflow flows",
+  "title": "Workflow Template Editor",
+  "description": "Create and edit workflow templates",
   "flow": {
     "title": "Flow",
     "flows": "Flows",
@@ -98,6 +98,9 @@
     "couldNotDuplicate": "Could not duplicate the flow",
     "flowExported": "Flow exported as JSON file",
     "noFlowToExport": "Create or load a flow first",
+    "saveBeforeExecute": "Please save the flow first",
+    "flowSent": "Flow Sent",
+    "sentToTerminal": "\"{name}\" sent to terminal for execution",
     "executionFailed": "Execution Failed",
     "couldNotExecute": "Could not start flow execution"
   },
@@ -152,8 +155,7 @@
     "export": "Export Flow",
     "templates": "Templates",
     "importTemplate": "Import Template",
-    "runWorkflow": "Run Workflow",
-    "monitor": "Monitor",
+    "sendToTerminal": "Send to Terminal",
     "savedFlows": "Saved Flows ({count})",
     "loading": "Loading...",
     "noSavedFlows": "No saved flows",