Summary

• add a cache-first strategy for bundled bun runtime assets during build/packaging
• enforce strict packaging policy: bundled bun files are copied only from the fixed cache directory
• support cross-platform cache locations and platform-specific runtime artifacts

Behavior

1. Check fixed cache directory for current <platform>-<arch> runtime
2. If cache exists, copy directly from cache into resources/bundled-bun/...
3. If cache is missing, download Bun runtime from official GitHub release assets into cache
4. Copy from cache into packaging resources (packaging never copies from system bun paths)

Cross-platform cache location

• Windows: %LOCALAPPDATA%/AionUi/cache/bundled-bun
• macOS: ~/Library/Caches/AionUi/bundled-bun
• Linux: ${XDG_CACHE_HOME:-~/.cache}/AionUi/bundled-bun
• Optional override: AIONUI_BUN_CACHE_DIR

Version control

• default runtime version: latest
• optional pin: AIONUI_BUN_VERSION (e.g. 1.2.20 or v1.2.20)

What changed

• update scripts/prepareBundledBun.js:
  • implement cache path resolution and validation
  • implement cache -> download fallback chain
  • remove direct system-path copy step from packaging flow
  • keep deterministic packaging by always copying from cache to resources
  • write manifest metadata: version, sourceType, cacheDir
• update integration test tests/integration/bundled-bun-packaged.test.ts:
  • validate sourceType is only cache or download
  • validate runtime files and manifest integrity

Verification

• packaging command:
  • node scripts/build-with-builder.js auto --win --x64 --dir
• validated packaged output includes:
  • out/win-unpacked/resources/bundled-bun/win32-x64/bun.exe
  • out/win-unpacked/resources/bundled-bun/win32-x64/bunx.exe
  • out/win-unpacked/resources/bundled-bun/win32-x64/manifest.json
• verified manifest contains strict cache metadata (sourceType=cache when cache is warm)
• checks:
  • bunx tsc --noEmit
  • bun run test:integration -- tests/integration/bundled-bun-packaged.test.ts

Notes

• this PR is focused on packaging/cache reliability only
• runtime usage/management of ACP agents through bundled bunx remains in a follow-up PR