feat(HAI-071): add Bun single-binary compile support for CLI

- Create build script (packages/cli/build.ts) using Bun.build compile target
- Update asset resolution in dashboard server for bundled context
- Add npm scripts to wire up the build process
- Add build-exe tests to verify compiled binary output
- Fix pre-existing build errors in engine and core packages
- Document build and compile workflow in README

package.json

@@ -8,6 +8,7 @@
     "dev": "tsx packages/cli/src/bin.ts",
     "dev:ui": "pnpm --filter @hai/dashboard dev",
     "build": "pnpm -r build",
+    "build:exe": "pnpm build && pnpm --filter hai build:exe",
     "typecheck": "pnpm -r typecheck"
   },
   "pnpm": {