## Summary
- Add source control-backed app sharing across onboarding, workspace
settings, available apps, and publish flows
- Introduce provider validation, permission checks, and workspace-scoped
read/write handling for shared apps
- Update worker/runtime integration, app bundle sync, and supporting
docs for the new flow

## Testing
- Not run (not requested)
- Added and updated unit coverage for runtime registry and opencode
model behavior
- Reviewed the affected onboarding, source control, and workspace routes
for the new shared-app flow