chore: migrate from bun to pnpm + vitest + esbuild

- Replace bun:test with vitest across all packages
- Replace bun build with esbuild
- Replace bun:sqlite with better-sqlite3
- Fix OCAS Store API: store.put/get → store.cas.put/get
- Fix vitest vi.mock hoisting (vi.hoisted)
- Add pnpm-workspace.yaml and pnpm-lock.yaml
- Update all package.json test/build scripts

WIP: 8 failures remain in agent-hermes (bun engines check + sqlite migration)

Refs #26

packages/util/__tests__/env.test.ts

@@ -1,4 +1,4 @@
-import { describe, expect, it } from "bun:test";
+import { describe, expect, it } from 'vitest';
 import { env } from "../src/env.js";
 
 describe("env", () => {

packages/util/__tests__/frontmatter-markdown.test.ts

@@ -1,4 +1,4 @@
-import { describe, expect, it } from "bun:test";
+import { describe, expect, it } from 'vitest';
 import type { AgentFrontmatter } from "../src/index.js";
 import { parseFrontmatterMarkdown, validateFrontmatter } from "../src/index.js";
 

packages/util/__tests__/process-logger.test.ts

@@ -1,4 +1,4 @@
-import { afterEach, describe, expect, test } from "bun:test";
+import { afterEach, describe, expect, test } from 'vitest';
 import { mkdirSync, mkdtempSync, readFileSync, rmSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";

packages/util/package.json

@@ -9,15 +9,14 @@
   "type": "module",
   "exports": {
     ".": {
-      "bun": "./src/index.ts",
       "types": "./dist/index.d.ts",
       "import": "./dist/index.js"
     }
   },
   "scripts": {
-    "prepublishOnly": "echo 'Use bun run release from repo root' && exit 1",
-    "test": "bun test __tests__/ src/__tests__/",
-    "test:ci": "bun test __tests__/ src/__tests__/"
+    "prepublishOnly": "echo 'Use pnpm run release from repo root' && exit 1",
+    "test": "vitest run __tests__/ src/__tests__/",
+    "test:ci": "vitest run __tests__/ src/__tests__/"
   },
   "dependencies": {},
   "devDependencies": {

packages/util/src/__tests__/ulid-timestamp.test.ts

@@ -1,4 +1,4 @@
-import { describe, expect, it } from "bun:test";
+import { describe, expect, it } from 'vitest';
 import { extractUlidTimestamp, generateUlid } from "../ulid.js";
 
 describe("extractUlidTimestamp", () => {