feat(HAI-076): add cross-compilation support for CLI executable builds

- Extend build.ts with cross-compilation targets for multiple platforms/architectures
- Add build:exe:all npm script to package.json for building all targets
- Add cross-compilation tests for build-exe-cross
- Add cross-compilation documentation section to README
- Clean up unused agent log, store, and route code across dashboard/core/engine packages

packages/cli/package.json

@@ -9,6 +9,7 @@
     "dev": "tsx src/bin.ts",
     "build": "tsc",
     "build:exe": "bun run build.ts",
+    "build:exe:all": "bun run build.ts --all",
     "typecheck": "tsc --noEmit",
     "test": "vitest run"
   },