Refactor large files into modular components

- Refactored page.tsx (613→252 lines) with GameOverScreen and LeftPanel extracted
- Refactored StatsTab.tsx (584→92 lines) with section components
- Refactored SkillsTab.tsx (434→54 lines) with sub-components
- Created modular structure for GameContext, LootInventory, and other components
- All extracted components organized into feature directories

src/lib/game/skill-evolution-modules/learning-skills.ts

@@ -0,0 +1,11 @@
+// ─── Learning/Study Skill Tier Definitions ─────────────────────────────
+// This file now re-exports from the split module files:
+// - quick-learner.ts: Quick Learner
+// - focused-mind.ts: Focused Mind
+// - knowledge-retention.ts: Knowledge Retention
+// - insight-harvest.ts: Insight Harvest
+
+export { QUICK_LEARNER_TIERS } from './quick-learner';
+export { FOCUSED_MIND_TIERS } from './focused-mind';
+export { KNOWLEDGE_RETENTION_TIERS } from './knowledge-retention';
+export { INSIGHT_HARVEST_TIERS } from './insight-harvest';