Add optional specialty type field to boss battles

Gym leaders, Elite Four, and champions can now have a Pokemon type
specialty (e.g. Rock, Water). Shown as a type image badge on boss
cards in the run view, and editable via dropdown in the admin form.
Includes migration, export, and seed pipeline support.

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

frontend/src/types/admin.ts

@@ -141,6 +141,7 @@ export interface PokemonEncounterLocation {
 export interface CreateBossBattleInput {
   name: string
   bossType: string
+  specialtyType?: string | null
   badgeName?: string | null
   badgeImageUrl?: string | null
   levelCap: number
@@ -154,6 +155,7 @@ export interface CreateBossBattleInput {
 export interface UpdateBossBattleInput {
   name?: string
   bossType?: string
+  specialtyType?: string | null
   badgeName?: string | null
   badgeImageUrl?: string | null
   levelCap?: number

frontend/src/types/game.ts

@@ -145,6 +145,7 @@ export interface BossBattle {
   versionGroupId: number
   name: string
   bossType: BossType
+  specialtyType: string | null
   badgeName: string | null
   badgeImageUrl: string | null
   levelCap: number