feat: Phase 2 — Thread lifecycle, execution engine, worker, CLI

- types.ts: START/END, RoleMeta, ThreadContext, Role, Moderator, WorkflowDefinition
- engine.ts: executeThread with JSONL persistence + AbortSignal
- worker.ts: per-bundle process, TCP IPC, kill individual threads
- CLI: run/ps/kill/threads/thread/thread rm commands
- 32 tests pass, biome clean

小橘 <xiaoju@shazhou.work>

tsconfig.json

@@ -15,8 +15,5 @@
     "composite": true,
     "outDir": "dist"
   },
-  "references": [
-    { "path": "packages/workflow" },
-    { "path": "packages/cli-workflow" }
-  ]
+  "references": [{ "path": "packages/workflow" }, { "path": "packages/cli-workflow" }]
 }