feat: league tier system + retrained V25 models (48 quality leagues)

- Add LeagueTier DB model and Prisma schema
- Add league-tiers service (CRUD, sync, retrain trigger)
- Add league-tiers controller with admin API endpoints
- Add /v1/admin/retrain endpoint in AI engine (extract→train→reload pipeline)
- Retrain V25 Pro with 48 quality leagues (MS accuracy: 26.9%→51.4%)
- Update qualified_leagues.json (443→48 leagues)
- Include V25 model files in repo for Docker deployment

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

prisma/schema.prisma

@@ -35,6 +35,7 @@ model League {
   country         Country?    @relation(fields: [countryId], references: [id])
   liveMatches     LiveMatch[]
   matches         Match[]
+  leagueTier      LeagueTier?
 
   @@unique([name, countryId, sport])
   @@index([sport])
@@ -807,6 +808,31 @@ model Translation {
   @@map("translations")
 }
 
+// ─────────────────────────────────────────────────────────────
+// League Tier System — Controls which leagues are used for
+// model training, live data fetching, and predictions.
+// Managed from admin panel. When a league is added/removed,
+// qualified_leagues.json is auto-regenerated and model
+// retraining is triggered.
+// ─────────────────────────────────────────────────────────────
+
+model LeagueTier {
+  id        Int      @id @default(autoincrement())
+  leagueId  String   @map("league_id")
+  tier      Int      @default(1) // 1=Elmas, 2=Altın, 3=Gümüş
+  isActive  Boolean  @default(true) @map("is_active")
+  addedBy   String?  @map("added_by") // admin user id
+  notes     String?  // e.g. "Margin 0.138, 828 maç"
+  createdAt DateTime @default(now()) @map("created_at")
+  updatedAt DateTime @updatedAt @map("updated_at")
+
+  league League @relation(fields: [leagueId], references: [id], onDelete: Cascade)
+
+  @@unique([leagueId])
+  @@index([tier, isActive])
+  @@map("league_tiers")
+}
+
 // ─────────────────────────────────────────────────────────────
 // Enums
 // ─────────────────────────────────────────────────────────────