chore(servers): remove quick/full scan buttons from server cards (#843)

Drops the Quick/Full scan actions and all supporting logic — they are no
longer needed. Removes the ServerScanActions component (incl. the unused
compact variant), the subsonicScan API, the scanStore, and the app-root
useScanPolling hook (no more background scan polling). Cleans up the
.server-scan-* CSS and the settings.scan i18n block across all 9 locales.

440 deletions, no new code; tsc + bundle clean.

src/api/subsonicScan.ts

@@ -1,23 +0,0 @@
-import { apiForServer } from './subsonicClient';
-
-export interface ScanStatus {
-  scanning: boolean;
-  count: number;
-  folderCount?: number;
-  lastScan?: string;
-}
-
-export async function startScan(serverId: string, fullScan: boolean): Promise<void> {
-  await apiForServer(serverId, 'startScan.view', fullScan ? { fullScan: 'true' } : {}, 10000);
-}
-
-export async function getScanStatus(serverId: string): Promise<ScanStatus> {
-  const data = await apiForServer<{ scanStatus?: ScanStatus }>(serverId, 'getScanStatus.view', {}, 8000);
-  const s = data.scanStatus;
-  return {
-    scanning: !!s?.scanning,
-    count: typeof s?.count === 'number' ? s.count : 0,
-    folderCount: typeof s?.folderCount === 'number' ? s.folderCount : undefined,
-    lastScan: typeof s?.lastScan === 'string' ? s.lastScan : undefined,
-  };
-}