refactor(api): 重构数据库访问为SQLAlchemy绑定的session

- 统一移除手动创建的数据库session，统一使用models模块中的db.session
- 修正项目创建接口，增加开始和结束日期的格式验证与处理
- 更新导入项目接口，使用枚举类型校验项目类型并优化异常处理
- 更新统计接口，避免多次查询假期数据，优化日期字符串处理
- 删除回滚前多余的session关闭调用，改为使用db.session.rollback()
- app.py中重构数据库初始化：统一配置SQLAlchemy，动态创建数据库路径和表
- 项目模型新增开始日期和结束日期字段支持
- 添加导入批次历史记录模型支持
- 优化工具函数中日期类型提示，移除无用导入
- 更新requirements.txt依赖版本回退，确保兼容性
- 前端菜单添加导入历史导航入口，实现页面访问路由绑定

backend/api/timerecords.py

@@ -1,31 +1,22 @@
 from flask import Blueprint, request, jsonify
-from sqlalchemy.orm import sessionmaker
-from sqlalchemy import create_engine, and_
-from backend.models.models import TimeRecord, Project, Holiday
-from backend.models.utils import *
+from sqlalchemy import and_
+from models.models import db, TimeRecord, Project, Holiday
+from models.utils import *
 from datetime import datetime, date
 import json
 
 timerecords_bp = Blueprint('timerecords', __name__)
 
-def get_db_session():
-    """获取数据库会话"""
-    engine = create_engine('sqlite:///data/timetrack.db')
-    Session = sessionmaker(bind=engine)
-    return Session()
-
 @timerecords_bp.route('/api/timerecords', methods=['GET'])
 def get_timerecords():
     """获取工时记录列表"""
     try:
-        session = get_db_session()
-        
         # 获取查询参数
         start_date = request.args.get('start_date')
         end_date = request.args.get('end_date')
         project_id = request.args.get('project_id')
         
-        query = session.query(TimeRecord)
+        query = db.session.query(TimeRecord).options(db.joinedload(TimeRecord.project))
         
         # 应用筛选条件
         if start_date:
@@ -45,7 +36,6 @@ def get_timerecords():
                 record_dict['day_of_week'] = get_day_of_week_chinese(record.date)
             result.append(record_dict)
         
-        session.close()
         return jsonify({'success': True, 'data': result})
     
     except Exception as e:
@@ -56,7 +46,6 @@ def create_timerecord():
     """创建工时记录"""
     try:
         data = request.json
-        session = get_db_session()
         
         # 验证必填字段
         if not data.get('date'):
@@ -65,7 +54,7 @@ def create_timerecord():
         record_date = datetime.strptime(data['date'], '%Y-%m-%d').date()
         
         # 检查是否为休息日
-        holidays = session.query(Holiday).all()
+        holidays = db.session.query(Holiday).all()
         holiday_info = is_holiday(record_date, holidays)
         
         # 计算工时
@@ -93,18 +82,17 @@ def create_timerecord():
             week_info=week_info
         )
         
-        session.add(record)
-        session.commit()
+        db.session.add(record)
+        db.session.commit()
         
         result = record.to_dict()
         if record.date:
             result['day_of_week'] = get_day_of_week_chinese(record.date)
         
-        session.close()
-        
         return jsonify({'success': True, 'data': result})
     
     except Exception as e:
+        db.session.rollback()
         return jsonify({'success': False, 'error': str(e)}), 500
 
 @timerecords_bp.route('/api/timerecords/<int:record_id>', methods=['PUT'])
@@ -112,11 +100,9 @@ def update_timerecord(record_id):
     """更新工时记录"""
     try:
         data = request.json
-        session = get_db_session()
         
-        record = session.query(TimeRecord).get(record_id)
+        record = db.session.query(TimeRecord).get(record_id)
         if not record:
-            session.close()
             return jsonify({'success': False, 'error': '记录不存在'}), 404
         
         # 更新字段
@@ -144,47 +130,41 @@ def update_timerecord(record_id):
         # 更新工作日状态
         record.is_working_on_holiday = record.is_holiday and record.hours not in ['-', '0:00']
         
-        session.commit()
+        db.session.commit()
         
         result = record.to_dict()
         if record.date:
             result['day_of_week'] = get_day_of_week_chinese(record.date)
         
-        session.close()
-        
         return jsonify({'success': True, 'data': result})
     
     except Exception as e:
+        db.session.rollback()
         return jsonify({'success': False, 'error': str(e)}), 500
 
 @timerecords_bp.route('/api/timerecords/<int:record_id>', methods=['DELETE'])
 def delete_timerecord(record_id):
     """删除工时记录"""
     try:
-        session = get_db_session()
-        
-        record = session.query(TimeRecord).get(record_id)
+        record = db.session.query(TimeRecord).get(record_id)
         if not record:
-            session.close()
             return jsonify({'success': False, 'error': '记录不存在'}), 404
         
-        session.delete(record)
-        session.commit()
-        session.close()
+        db.session.delete(record)
+        db.session.commit()
         
         return jsonify({'success': True, 'message': '记录已删除'})
     
     except Exception as e:
+        db.session.rollback()
         return jsonify({'success': False, 'error': str(e)}), 500
 
 @timerecords_bp.route('/api/timerecords/check_holiday/<string:date_str>', methods=['GET'])
 def check_holiday(date_str):
     """检查指定日期是否为休息日"""
     try:
-        session = get_db_session()
-        
         check_date = datetime.strptime(date_str, '%Y-%m-%d').date()
-        holidays = session.query(Holiday).all()
+        holidays = db.session.query(Holiday).all()
         holiday_info = is_holiday(check_date, holidays)
         
         result = {
@@ -196,7 +176,6 @@ def check_holiday(date_str):
             'week_info': get_week_info(check_date)
         }
         
-        session.close()
         return jsonify({'success': True, 'data': result})
     
     except Exception as e: