feat: add channel categories and improved creator detection

- Add category field to TelegramChannel (filterable tag like STL, PDF, D&D)
- Category column in channels table with edit via dropdown menu
- Improved creator extraction: filename patterns + channel title fallback
- extractCreatorFromChannelTitle strips [Completed], (Paid), emoji, etc.
- Fix ArchiveType in PackageListItem and PackageRow for new types
- Add Prisma migration for category column

prisma/schema.prisma

@@ -421,6 +421,7 @@ model TelegramChannel {
   type       ChannelType
   isForum    Boolean     @default(false)
   isActive   Boolean     @default(false)
+  category   String?     @db.VarChar(64)
   createdAt  DateTime    @default(now())
   updatedAt  DateTime    @updatedAt
 
@@ -428,6 +429,7 @@ model TelegramChannel {
   packages    Package[]
 
   @@index([type, isActive])
+  @@index([category])
   @@map("telegram_channels")
 }