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/data_import.py

@@ -0,0 +1,118 @@
+from flask import Blueprint, request, jsonify
+from models.models import db, Project, TimeRecord, Holiday, ImportBatch
+from models.utils import calculate_hours, is_holiday, get_week_info
+from datetime import datetime
+import re
+import json
+
+data_import_bp = Blueprint('data_import', __name__)
+
+@data_import_bp.route('/import', methods=['POST'])
+def import_records():
+    """批量导入工时记录并记录导入历史"""
+    data = request.json
+    records_text = data.get('records', '')
+    lines = records_text.strip().split('\n')
+    total_records = len([line for line in lines if line.strip()])
+    
+    success_count = 0
+    failures = []
+    
+    projects = {p.project_name: p for p in Project.query.all()}
+    holidays = Holiday.query.all()
+    current_year = datetime.now().year
+
+    for i, line in enumerate(lines):
+        line = line.strip()
+        if not line:
+            continue
+
+        match = re.match(r'^(\d{1,2})月(\d{1,2})日\s+(.+?)\s+(\d{1,2}:\d{2})\s+(\d{1,2}:\d{2})\s+(.*)$', line)
+        
+        if not match:
+            failures.append({'line': line, 'reason': '格式不匹配'})
+            continue
+            
+        try:
+            month, day, project_name, start_time_str, end_time_str, activity_num = match.groups()
+            project_name = project_name.strip()
+            activity_num = activity_num.strip()
+
+            record_date = datetime(current_year, int(month), int(day)).date()
+            
+            if project_name not in projects:
+                failures.append({'line': line, 'reason': f'项目 "{project_name}" 不存在'})
+                continue
+            
+            project = projects[project_name]
+            start_time = datetime.strptime(start_time_str, '%H:%M').time()
+            end_time = datetime.strptime(end_time_str, '%H:%M').time()
+            
+            holiday_info = is_holiday(record_date, holidays)
+            hours = calculate_hours(start_time_str, end_time_str, holiday_info['is_holiday'])
+            week_info = get_week_info(record_date)
+
+            record = TimeRecord(
+                date=record_date,
+                event_description=f"批量导入 - {project_name}",
+                project_id=project.id,
+                start_time=start_time,
+                end_time=end_time,
+                activity_num=activity_num,
+                hours=hours,
+                is_holiday=holiday_info['is_holiday'],
+                is_working_on_holiday=holiday_info['is_holiday'] and hours not in ['-', '0:00'],
+                holiday_type=holiday_info['holiday_type'],
+                week_info=week_info
+            )
+            db.session.add(record)
+            success_count += 1
+
+        except Exception as e:
+            failures.append({'line': line, 'reason': str(e)})
+
+    # 决定导入状态
+    status = "失败"
+    if success_count == total_records and total_records > 0:
+        status = "成功"
+    elif success_count > 0:
+        status = "部分成功"
+
+    # 创建并保存导入批次记录
+    batch = ImportBatch(
+        status=status,
+        success_count=success_count,
+        failure_count=len(failures),
+        total_records=total_records,
+        source_preview='\n'.join(lines[:5]), # 保存前5行作为预览
+        failures_log=json.dumps(failures, ensure_ascii=False) if failures else None
+    )
+    db.session.add(batch)
+
+    try:
+        db.session.commit()
+    except Exception as e:
+        db.session.rollback()
+        return jsonify({
+            'success': False, 
+            'error': f'数据库提交失败: {str(e)}',
+            'success_count': 0,
+            'failure_count': total_records,
+            'failures': [{'line': l, 'reason': '数据库错误'} for l in lines]
+        }), 500
+
+    return jsonify({
+        'success': success_count > 0,
+        'success_count': success_count,
+        'failure_count': len(failures),
+        'failures': failures
+    })
+
+@data_import_bp.route('/import/history', methods=['GET'])
+def get_import_history():
+    """获取导入历史记录"""
+    try:
+        history = ImportBatch.query.order_by(ImportBatch.import_date.desc()).all()
+        return jsonify([h.to_dict() for h in history])
+    except Exception as e:
+        return jsonify({'success': False, 'error': str(e)}), 500