feat(09-01): add scan control events and cancelled metrics field

- Add LibraryScanCancelled, LibraryScanPaused, LibraryScanResumed events
- Regenerate frontend/src/events.ts via go generate
- Add Cancelled bool field to ScanMetrics struct

frontend/src/events.ts

@@ -19,6 +19,7 @@ export const Events = {
     ThemeConfigChanged: "ThemeConfigChanged",
     TrackListConfigChanged: "TrackListConfigChanged",
     FavoritesConfigChanged: "FavoritesConfigChanged",
+    ShortcutsConfigChanged: "ShortcutsConfigChanged",
 
     // Playlist events
     PlaylistCreated: "PlaylistCreated",
@@ -32,6 +33,11 @@ export const Events = {
     LibraryScanStarted: "LibraryScanStarted",
     LibraryScanProgress: "LibraryScanProgress",
     LibraryScanComplete: "LibraryScanComplete",
+
+    // Scan control events
+    LibraryScanCancelled: "LibraryScanCancelled",
+    LibraryScanPaused: "LibraryScanPaused",
+    LibraryScanResumed: "LibraryScanResumed",
 } as const;
 
 export type EventName = (typeof Events)[keyof typeof Events];