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/components/game/LootInventory/icons.ts

@@ -0,0 +1,15 @@
+import { Gem, Sparkles, Scroll, Droplet, Trash2, Search, 
+  Package, Sword, Shield, Shirt, Crown, ArrowUpDown,
+  Wrench, AlertTriangle } from 'lucide-react';
+import type { EquipmentCategory } from '@/lib/game/data/equipment';
+
+export const CATEGORY_ICONS: Record<string, typeof Sword> = {
+  caster: Sword,
+  shield: Shield,
+  catalyst: Sparkles,
+  head: Crown,
+  body: Shirt,
+  hands: Wrench,
+  feet: Package,
+  accessory: Gem,
+};