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/cli/package.json

@@ -11,8 +11,8 @@
     "uwf": "./dist/cli.js"
   },
   "dependencies": {
-    "@ocas/core": "^0.1.1",
-    "@ocas/fs": "^0.1.1",
+    "@ocas/core": "^0.2.2",
+    "@ocas/fs": "^0.2.2",
     "@united-workforce/protocol": "workspace:^",
     "@united-workforce/util": "workspace:^",
     "@united-workforce/util-agent": "workspace:^",
@@ -22,9 +22,9 @@
     "yaml": "^2.8.4"
   },
   "scripts": {
-    "prepublishOnly": "echo 'Use bun run release from repo root' && exit 1",
-    "test": "bun test src/",
-    "test:ci": "bun test src/"
+    "prepublishOnly": "echo 'Use pnpm run release from repo root' && exit 1",
+    "test": "vitest run src/",
+    "test:ci": "vitest run src/"
   },
   "publishConfig": {
     "access": "public"