Add pokemon status management with death tracking

Implement status change workflow (alive → dead) with confirmation modal,
death cause recording, and visual status indicators on pokemon cards.
Includes backend migration for death_cause field and graveyard view
on the run dashboard.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/components/index.ts

@@ -4,6 +4,7 @@ export { GameGrid } from './GameGrid'
 export { Layout } from './Layout'
 export { PokemonCard } from './PokemonCard'
 export { RuleBadges } from './RuleBadges'
+export { StatusChangeModal } from './StatusChangeModal'
 export { RuleToggle } from './RuleToggle'
 export { RulesConfiguration } from './RulesConfiguration'
 export { StatCard } from './StatCard'