feat(albums): compilation filter toggle in All Albums

Tri-state button (all / only compilations / hide compilations) in the
Albums page header, using the OpenSubsonic isCompilation tag from
Navidrome. Client-side filter via useMemo, no extra server calls.
Closes #65.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/locales/en.ts

@@ -291,6 +291,12 @@ export const enTranslation = {
     yearTo: 'To',
     yearFilterClear: 'Clear year filter',
     yearFilterLabel: 'Year',
+    compilationLabel: 'Compilations',
+    compilationOnly: 'Only compilations',
+    compilationHide: 'Hide compilations',
+    compilationTooltipAll: 'All albums · click: only compilations',
+    compilationTooltipOnly: 'Only compilations · click: hide compilations',
+    compilationTooltipHide: 'Compilations hidden · click: show all',
     select: 'Multi-select',
     startSelect: 'Enable multi-select',
     cancelSelect: 'Cancel',