feat: Implement genre activation/deactivation with UI controls and main page filtering.

prisma/schema.prisma

@@ -30,6 +30,7 @@ model Genre {
   id    Int    @id @default(autoincrement())
   name  String @unique
   subtitle String?
+  active   Boolean @default(true)
   songs Song[]
   dailyPuzzles DailyPuzzle[]
 }