538d367cc4
Add internal/assets package that downloads and caches app assets from Hub API with SHA-256 change detection. Assets resolve from synced cache first, falling back to baked-in directory. Daily sync schedule + on-demand POST /api/assets/sync endpoint. Config: assets.sync_enabled + assets.sync_schedule (default 05:00) Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>