feat(mobile): add iOS profile support with build detection
- Auto-detect App Store/TestFlight vs Xcode builds via receipt check
- Per-profile database files (peek-default.db, peek-dev.db, etc.)
- Append ?profile= to all sync URLs for server-side isolation
- Profile selector in Settings with quick-switch buttons
- Visual banner when not on default profile
- Debug tools for container inspection and database export
- Build scripts for clean iOS rebuilds (npm run rebuild:ios)