- Pause/Resume buttons replace Soft Scan/Full Rescan during active scan
- Cancel button shows confirmation dialog with Keep/Discard/Continue options
- Register LibraryScanPaused/Resumed/Cancelled event handlers
- Status bar shows 'Scan paused.' with accent color when paused
- Add CancelScan/PauseScan/ResumeScan Wails binding stubs
- Cancel dialog overlay dismissible by clicking outside or Continue Scanning
- Add cancelled field to ScanMetrics TypeScript interface