Initial commit: Text Adventure Game

Features:
- Combat system with AP/EP hit calculation and three-layer defense
- Auto-combat/farming mode
- Item system with stacking support
- Skill system with levels, milestones, and parent skill sync
- Shop system with dynamic pricing
- Inventory management with bulk selling
- Event system
- Game loop with offline earnings
- Save/Load system

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

vitest.config.js

@@ -0,0 +1,9 @@
+/// <reference types="vitest" />
+import { defineConfig } from 'vitest/config'
+
+export default defineConfig({
+  test: {
+    include: ['tests/**/*.spec.{js,mjs}'],
+    exclude: ['node_modules/']
+  }
+})