feat: Phase 3 — engine read path + runtime context builder

- Add buildThreadContext(headHash, cas) to workflow-runtime
- Expand extract phase to return { meta, contentPayload, refs[] }
- Add parseCasThreadNode() to workflow-cas for node type parsing
- Update createWorkflow to write ContentMerkleNode with artifact refs
- Tests: 4 pass (build-context + extract-refs)
- Biome format pass on all files

Refs #155, closes #158

小橘 <xiaoju@shazhou.work>

packages/cli-workflow/__tests__/commands.test.ts

@@ -2,10 +2,9 @@ import { afterEach, beforeEach, describe, expect, test } from "bun:test";
 import { mkdir, mkdtemp, readFile, rm, unlink, writeFile } from "node:fs/promises";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
-
-import { getGlobalCasDir } from "@uncaged/workflow-util";
 import { createContentMerkleNode, serializeMerkleNode } from "@uncaged/workflow-cas";
 import { getRegisteredWorkflow, readWorkflowRegistry } from "@uncaged/workflow-register";
+import { getGlobalCasDir } from "@uncaged/workflow-util";
 import { cmdCasGet, cmdCasList, cmdCasPut, cmdCasRm } from "../src/commands/cas/index.js";
 import {
   cmdAdd,

packages/cli-workflow/__tests__/gc-cli.test.ts

@@ -5,8 +5,8 @@ import { tmpdir } from "node:os";
 import { join } from "node:path";
 import { fileURLToPath } from "node:url";
 import { createCasStore, putContentMerkleNode } from "@uncaged/workflow-cas";
-import { getGlobalCasDir } from "@uncaged/workflow-util";
 import { garbageCollectCas } from "@uncaged/workflow-execute";
+import { getGlobalCasDir } from "@uncaged/workflow-util";
 import { cmdThreadRemove } from "../src/commands/thread/index.js";
 import { pathExists } from "../src/fs-utils.js";