Initial commit: Cosmic Garden idle game foundation

- Complete game architecture with modular JS structure
- 12 buildings across 4 tiers with scaling costs
- 15+ upgrades with requirements and bonuses
- 20 achievements to unlock
- Auto-save system with offline progress (50% efficiency)
- Export/Import save functionality
- Responsive dark-themed UI with cosmic aesthetic
- Floating text animations and notification system

js/main.js

@@ -0,0 +1,14 @@
+/**
+ * Cosmic Garden - Main Entry Point
+ */
+
+document.addEventListener('DOMContentLoaded', () => {
+    Game.init();
+    
+    // Show last save time
+    const lastSave = SaveSystem.getLastSaveTime();
+    if (lastSave) {
+        document.getElementById('last-saved').textContent = 
+            `Last saved: ${lastSave.toLocaleTimeString()}`;
+    }
+});