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/GameContext/context-create.ts

@@ -0,0 +1,4 @@
+import { createContext } from 'react';
+import type { GameContextValue } from './types';
+
+export const GameContext = createContext<GameContextValue | null>(null);