Add complete item collection system (v0.2.0)

🎒 Item Collection System:
- 16 unique items across 5 categories (healing, battle, rare, location, special)
- Rarity tiers: Common, Uncommon, Rare, Epic, Legendary with symbols
- 30% chance to find items during exploration
- Location-specific items (shells, mushrooms, crystals, runes)
- Inventory management with \!inventory and \!use commands
- Web interface integration showing player inventories
- Consumable items: healing potions, battle boosters, lucky charms

🔧 Technical Updates:
- Added items and player_inventory database tables
- New Inventory module for item management
- Updated game engine with item discovery system
- Enhanced web interface with inventory display
- Item initialization from config/items.json

🆕 New Commands:
- \!inventory / \!inv / \!items - View collected items by category
- \!use <item name> - Use consumable items on active pets

🤖 Generated with [Claude Code](https://claude.ai/code)

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

modules/__init__.py

@@ -7,6 +7,7 @@ from .battle_system import BattleSystem
 from .pet_management import PetManagement
 from .achievements import Achievements
 from .admin import Admin
+from .inventory import Inventory
 
 __all__ = [
     'CoreCommands',
@@ -14,5 +15,6 @@ __all__ = [
     'BattleSystem',
     'PetManagement',
     'Achievements',
-    'Admin'
+    'Admin',
+    'Inventory'
 ]