去除一些无用功能，以前的UI这些。

db/tasks.py

@@ -1,76 +0,0 @@
-# -*- coding: utf-8 -*-
-from datetime import datetime
-from typing import Dict, List, Optional
-
-from db.base import BaseDBOperator
-from db.connection import DBConnectionManager
-
-
-class TasksDB(BaseDBOperator):
-    """任务管理相关数据库操作"""
-    
-    def __init__(self, db_manager: DBConnectionManager):
-        super().__init__(db_manager)
-    
-    def initialize_table(self) -> bool:
-        """初始化任务表"""
-        sql = """
-        CREATE TABLE IF NOT EXISTS tasks (
-            task_id INT AUTO_INCREMENT PRIMARY KEY,
-            task_description VARCHAR(255) NOT NULL,
-            reminder_time TIME NOT NULL,
-            task_type ENUM('single', 'recurring') DEFAULT 'single',
-            status ENUM('pending', 'completed') DEFAULT 'pending',
-            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
-        )
-        """
-        return self.execute_update(sql)
-    
-    def add_task(self, description: str, reminder_time: str, task_type: str = 'single') -> Optional[int]:
-        """添加任务"""
-        sql = """
-        INSERT INTO tasks (task_description, reminder_time, task_type)
-        VALUES (%s, %s, %s)
-        """
-        conn = self.db_manager.get_mysql_connection()
-        try:
-            with conn.cursor() as cursor:
-                cursor.execute(sql, (description, reminder_time, task_type))
-                task_id = cursor.lastrowid
-            conn.commit()
-            return task_id
-        except Exception as e:
-            self.LOG.error(f"添加任务出错: {e}")
-            conn.rollback()
-            return None
-        finally:
-            conn.close()
-    
-    def get_pending_tasks(self) -> List[Dict]:
-        """获取待办任务"""
-        sql = """
-        SELECT task_id, task_description, reminder_time, task_type, status, created_at
-        FROM tasks
-        WHERE status = 'pending'
-        ORDER BY reminder_time
-        """
-        return self.execute_query(sql) or []
-    
-    def complete_task(self, task_id: int) -> bool:
-        """完成任务"""
-        sql = """
-        UPDATE tasks
-        SET status = 'completed'
-        WHERE task_id = %s
-        """
-        return self.execute_update(sql, (task_id,))
-    
-    def get_tasks_by_time(self, current_time: str) -> List[Dict]:
-        """获取指定时间的任务"""
-        sql = """
-        SELECT task_id, task_description, reminder_time, task_type
-        FROM tasks
-        WHERE TIME_FORMAT(reminder_time, '%H:%i') = %s
-          AND (status = 'pending' OR (status = 'completed' AND task_type = 'recurring'))
-        """
-        return self.execute_query(sql, (current_time,)) or []