fix: 修复 market.py _put_db 拼写错误和多处连接泄漏

- market.py:308: _put_db(conn) → put_db(_conn) 修复函数名和变量名拼写错误
- market.py: get_fundamental put_db 移到 finally，初始化 conn=None 防 NameError
- admin.py: kline_sync_status 和 admin_scan_status put_db 移到 finally

stock-html/routes/admin.py

@@ -782,7 +782,6 @@ def kline_sync_status():
         total_stocks = cur.fetchone()[0]
 
         cur.close()
-        put_db(conn)
 
         is_running = _is_kline_sync_running()
 
@@ -858,6 +857,8 @@ def kline_sync_status():
         })
     except Exception as e:
         return jsonify({'success': False, 'error': str(e)}), 500
+    finally:
+        put_db(conn)
 
 
 # ========== 定时任务监控 ==========
@@ -1301,7 +1302,6 @@ def admin_scan_status():
         triggered = cur.fetchone()[0]
 
         cur.close()
-        put_db(conn)
 
         is_running = _is_scan_running()
 
@@ -1350,3 +1350,5 @@ def admin_scan_status():
         })
     except Exception as e:
         return jsonify({'success': False, 'error': str(e)}), 500
+    finally:
+        put_db(conn)