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/dashboard/package.json

@@ -4,10 +4,10 @@
   "private": true,
   "type": "module",
   "scripts": {
-    "dev": "bun server.ts",
+    "dev": "npx tsx server.ts",
     "build": "vite build",
-    "test": "bun test src/",
-    "test:ci": "bun test src/"
+    "test": "vitest run src/",
+    "test:ci": "vitest run src/"
   },
   "dependencies": {
     "@base-ui/react": "^1.5.0",
@@ -29,12 +29,12 @@
   },
   "devDependencies": {
     "@tailwindcss/vite": "^4.3.0",
-    "@types/bun": "^1.2.14",
     "@types/react": "^19.2.14",
     "@types/react-dom": "^19.2.3",
     "@vitejs/plugin-react": "^6.0.2",
     "tailwindcss": "^4.2.4",
     "typescript": "^5.8.3",
-    "vite": "^8.0.13"
+    "vite": "^8.0.13",
+    "@types/node": "^25.7.0"
   }
 }