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/pages/RunEncounters.tsx

@@ -15,6 +15,7 @@ import {
   RuleBadges,
   ShinyBox,
   ShinyEncounterModal,
+  TypeBadge,
 } from '../components'
 import { BossDefeatModal } from '../components/BossDefeatModal'
 import type {
@@ -1097,6 +1098,9 @@ export function RunEncounters() {
                             <span className="px-2 py-0.5 text-xs font-medium rounded-full bg-gray-100 dark:bg-gray-700 text-gray-600 dark:text-gray-300">
                               {bossTypeLabel[boss.bossType] ?? boss.bossType}
                             </span>
+                            {boss.specialtyType && (
+                              <TypeBadge type={boss.specialtyType} />
+                            )}
                           </div>
                           <p className="text-xs text-gray-500 dark:text-gray-400">
                             {boss.location} &middot; Level Cap: {boss.levelCap}