fix(danding_points): improve conn management in api.py

- Read methods (get_balance/get_transactions/get_ranking): add try/except/finally
- Write methods (add/spend/set_points): add rollback() before early return conn.close()
- Prevents connection leaks on exceptions and early returns

danding_bot/plugins/danding_points/api.py

@@ -59,6 +59,7 @@ class PointsAPI:
                     new_balance = current_balance + amount
                     if self.config.POINTS_MAX_BALANCE > 0:
                         if new_balance > self.config.POINTS_MAX_BALANCE:
+                            conn.rollback()
                             conn.close()
                             return False, current_balance
 
@@ -130,6 +131,7 @@ class PointsAPI:
 
                     # Check sufficient balance
                     if current_balance < amount:
+                        conn.rollback()
                         conn.close()
                         return False, current_balance
 
@@ -198,6 +200,7 @@ class PointsAPI:
 
                     # If new value equals old value, return without writing
                     if current_balance == amount:
+                        conn.rollback()
                         conn.close()
                         return True, amount
 
@@ -250,6 +253,7 @@ class PointsAPI:
 
         def _get():
             conn = self.db.get_connection()
+            try:
                 cursor = conn.cursor()
                 cursor.execute(
                     """
@@ -262,8 +266,12 @@ class PointsAPI:
                     (user_id, limit, offset),
                 )
                 rows = cursor.fetchall()
-            conn.close()
                 return [dict(row) for row in rows]
+            except Exception as e:
+                logger.error(f"get_transactions failed for {user_id}: {e}")
+                return []
+            finally:
+                conn.close()
 
         return await asyncio.to_thread(_get)
 
@@ -281,8 +289,8 @@ class PointsAPI:
 
         def _get():
             conn = self.db.get_connection()
+            try:
                 cursor = conn.cursor()
-
                 order_column = "points" if order_by == "points" else "total_earned"
                 query = f"""
                     SELECT
@@ -297,7 +305,11 @@ class PointsAPI:
                 """
                 cursor.execute(query, (limit,))
                 rows = cursor.fetchall()
-            conn.close()
                 return [dict(row) for row in rows]
+            except Exception as e:
+                logger.error(f"get_ranking failed: {e}")
+                return []
+            finally:
+                conn.close()
 
         return await asyncio.to_thread(_get)