Unify all handler signatures and simplify router

- Standardize all handlers to signature: (query, user_id, player, data=None)
- Replace 125-line if/elif chain with HANDLER_MAP dictionary
- Reduce router code by 90 lines (72% reduction)
- Add HANDLER_MAP registry for cleaner organization
- Enable future auto-discovery and decorator patterns
- Maintain full backward compatibility
- Document changes in HANDLER_REFACTORING_V2.md

Benefits:
- O(1) handler lookup vs O(n) if/elif chain
- Add new handlers by just updating the map
- Consistent signature makes code easier to understand
- Opens doors for middleware and hooks

bot/inventory_handlers.py

@@ -10,8 +10,8 @@ from data.items import ITEMS
 logger = logging.getLogger(__name__)
 
 
-async def handle_inventory_menu(query, user_id: int, player: dict):
-    """Show player inventory."""
+async def handle_inventory_menu(query, user_id: int, player: dict, data: list = None):
+    """Display player inventory with item management options."""
     await query.answer()
     inventory_items = await database.get_inventory(user_id)