Add missing get_active_pets method to database

- Added get_active_pets() method that returns all active pets for a player
- Method includes pet details and species information needed for gym battles
- Fixes "get_active_pets" AttributeError in gym challenge command

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

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

src/database.py

@@ -739,6 +739,21 @@ class Database:
             await db.commit()
             return True
     
+    async def get_active_pets(self, player_id: int) -> List[Dict]:
+        """Get all active pets for a player"""
+        async with aiosqlite.connect(self.db_path) as db:
+            db.row_factory = aiosqlite.Row
+            cursor = await db.execute("""
+                SELECT p.*, ps.name as species_name, ps.type1, ps.type2,
+                       ps.base_hp, ps.base_attack, ps.base_defense, ps.base_speed
+                FROM pets p
+                JOIN pet_species ps ON p.species_id = ps.id
+                WHERE p.player_id = ? AND p.is_active = 1
+                ORDER BY p.id ASC
+            """, (player_id,))
+            rows = await cursor.fetchall()
+            return [dict(row) for row in rows]
+    
     # Gym Battle System Methods
     async def get_gyms_in_location(self, location_id: int, player_id: int = None) -> List[Dict]:
         """Get all gyms in a specific location with optional player progress"""