feat: add orchestrator execution engine, observability panel, and LSP document caching

Wire FlowExecutor into orchestrator routes for actual flow execution with
pause/resume/stop lifecycle management. Add CLI session audit system with
audit-routes backend and Observability tab in IssueHub frontend. Introduce
cli-session-mux for cross-workspace session routing and QueueSendToOrchestrator
UI component. Normalize frontend API response handling for { data: ... }
wrapper format and propagate projectPath through flow hooks.

In codex-lens, add per-server opened-document cache in StandaloneLspManager
to avoid redundant didOpen notifications (using didChange for updates), and
skip warmup delay for already-warmed LSP server instances in ChainSearchEngine.

ccw/src/core/services/cli-session-mux.ts

@@ -0,0 +1,24 @@
+/**
+ * CliSessionMux
+ *
+ * A tiny indirection layer used by FlowExecutor (and potentially others) to
+ * route commands to existing PTY sessions in a testable way.
+ *
+ * Why this exists:
+ * - ESM module namespace exports are immutable, which makes it hard to mock
+ *   named exports in node:test without special loaders.
+ * - Exporting a mutable object lets tests override behavior by swapping
+ *   functions on the object.
+ */
+
+import type { CliSessionManager } from './cli-session-manager.js';
+import { findCliSessionManager, getCliSessionManager } from './cli-session-manager.js';
+
+export const cliSessionMux: {
+  findCliSessionManager: (sessionKey: string) => CliSessionManager | null;
+  getCliSessionManager: (projectRoot?: string) => CliSessionManager;
+} = {
+  findCliSessionManager,
+  getCliSessionManager,
+};
+