feat: recreate Debug Tab with modular debugging functions

- Add DebugTab.tsx as main container with collapsible sections
- Add 8 debug section components in DebugTab/ subdirectory:
  - GameStateDebugSection: reset, mana, time, pause controls
  - DisciplineDebugSection: activate/deactivate, add XP
  - AttunementDebugSection: unlock, add XP
  - ElementDebugSection: unlock all, add elemental mana
  - GolemDebugSection: enable/disable golems
  - PactDebugSection: force sign/clear pacts
  - SpireDebugSection: jump floors, toggle spire mode
  - AchievementDebugSection: unlock/reset achievements
- Add DebugTab to barrel export (tabs/index.ts)
- Add lazy-loaded Debug tab to page.tsx
- Add DebugTab.test.ts with 45 tests
- All files under 400 lines
- Uses existing debug context (DebugProvider, DebugName)
- Destructive actions require confirmation (double-click pattern)

src/components/game/tabs/index.ts

@@ -4,4 +4,5 @@
 export { DisciplinesTab } from './DisciplinesTab';
 export { SpellsTab } from './SpellsTab';
 export { StatsTab } from './StatsTab';
+export { DebugTab } from './DebugTab';
 export { AchievementsTab } from './AchievementsTab';