feat: 实现 KPL 系统功能改进计划

1. 课程学习进度追踪
   - 新增 UserCourseProgress 和 UserMaterialProgress 模型
   - 新增 /api/v1/progress/* 进度追踪 API
   - 更新 admin.py 使用真实课程完成率数据

2. 路由权限检查完善
   - 新增前端 permissionChecker.ts 权限检查工具
   - 更新 router/guard.ts 实现团队和课程权限验证
   - 新增后端 permission_service.py

3. AI 陪练音频转文本
   - 新增 speech_recognition.py 语音识别服务
   - 新增 /api/v1/speech/* API
   - 更新 ai-practice-coze.vue 支持语音输入

4. 双人对练报告生成
   - 更新 practice_room_service.py 添加报告生成功能
   - 新增 /rooms/{room_code}/report API
   - 更新 duo-practice-report.vue 调用真实 API

5. 学习提醒推送
   - 新增 notification_service.py 通知服务
   - 新增 scheduler_service.py 定时任务服务
   - 支持钉钉、企微、站内消息推送

6. 智能学习推荐
   - 新增 recommendation_service.py 推荐服务
   - 新增 /api/v1/recommendations/* API
   - 支持错题、能力、进度、热门多维度推荐

7. 安全问题修复
   - DEBUG 默认值改为 False
   - 添加 SECRET_KEY 安全警告
   - 新增 check_security_settings() 检查函数

8. 证书 PDF 生成
   - 更新 certificate_service.py 添加 PDF 生成
   - 添加 weasyprint、Pillow、qrcode 依赖
   - 更新下载 API 支持 PDF 和 PNG 格式

backend/app/models/user_course_progress.py

@@ -0,0 +1,201 @@
+"""
+用户课程学习进度数据库模型
+"""
+from enum import Enum
+from typing import Optional
+from datetime import datetime
+
+from sqlalchemy import (
+    String,
+    Integer,
+    Boolean,
+    ForeignKey,
+    Float,
+    DateTime,
+    UniqueConstraint,
+    Index,
+)
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from app.models.base import BaseModel
+
+
+class ProgressStatus(str, Enum):
+    """学习进度状态枚举"""
+    NOT_STARTED = "not_started"  # 未开始
+    IN_PROGRESS = "in_progress"  # 学习中
+    COMPLETED = "completed"  # 已完成
+
+
+class UserCourseProgress(BaseModel):
+    """
+    用户课程进度表
+    记录用户对每门课程的整体学习进度
+    """
+
+    __tablename__ = "user_course_progress"
+    __table_args__ = (
+        UniqueConstraint("user_id", "course_id", name="uq_user_course"),
+        Index("idx_user_course_progress_user", "user_id"),
+        Index("idx_user_course_progress_course", "course_id"),
+        Index("idx_user_course_progress_status", "status"),
+    )
+
+    user_id: Mapped[int] = mapped_column(
+        Integer,
+        ForeignKey("users.id", ondelete="CASCADE"),
+        nullable=False,
+        comment="用户ID",
+    )
+    course_id: Mapped[int] = mapped_column(
+        Integer,
+        ForeignKey("courses.id", ondelete="CASCADE"),
+        nullable=False,
+        comment="课程ID",
+    )
+    
+    # 进度信息
+    status: Mapped[ProgressStatus] = mapped_column(
+        String(20),
+        default=ProgressStatus.NOT_STARTED.value,
+        nullable=False,
+        comment="学习状态：not_started/in_progress/completed",
+    )
+    progress_percent: Mapped[float] = mapped_column(
+        Float,
+        default=0.0,
+        nullable=False,
+        comment="完成百分比(0-100)",
+    )
+    completed_materials: Mapped[int] = mapped_column(
+        Integer,
+        default=0,
+        nullable=False,
+        comment="已完成资料数",
+    )
+    total_materials: Mapped[int] = mapped_column(
+        Integer,
+        default=0,
+        nullable=False,
+        comment="总资料数",
+    )
+    
+    # 学习时长统计
+    total_study_time: Mapped[int] = mapped_column(
+        Integer,
+        default=0,
+        nullable=False,
+        comment="总学习时长(秒)",
+    )
+    
+    # 时间记录
+    first_accessed_at: Mapped[Optional[datetime]] = mapped_column(
+        DateTime,
+        nullable=True,
+        comment="首次访问时间",
+    )
+    last_accessed_at: Mapped[Optional[datetime]] = mapped_column(
+        DateTime,
+        nullable=True,
+        comment="最后访问时间",
+    )
+    completed_at: Mapped[Optional[datetime]] = mapped_column(
+        DateTime,
+        nullable=True,
+        comment="完成时间",
+    )
+    
+    # 关联关系
+    user = relationship("User", backref="course_progress")
+    course = relationship("Course", backref="user_progress")
+
+
+class UserMaterialProgress(BaseModel):
+    """
+    用户资料进度表
+    记录用户对每个课程资料的学习进度
+    """
+
+    __tablename__ = "user_material_progress"
+    __table_args__ = (
+        UniqueConstraint("user_id", "material_id", name="uq_user_material"),
+        Index("idx_user_material_progress_user", "user_id"),
+        Index("idx_user_material_progress_material", "material_id"),
+    )
+
+    user_id: Mapped[int] = mapped_column(
+        Integer,
+        ForeignKey("users.id", ondelete="CASCADE"),
+        nullable=False,
+        comment="用户ID",
+    )
+    material_id: Mapped[int] = mapped_column(
+        Integer,
+        ForeignKey("course_materials.id", ondelete="CASCADE"),
+        nullable=False,
+        comment="资料ID",
+    )
+    course_id: Mapped[int] = mapped_column(
+        Integer,
+        ForeignKey("courses.id", ondelete="CASCADE"),
+        nullable=False,
+        comment="课程ID（冗余字段，便于查询）",
+    )
+    
+    # 进度信息
+    is_completed: Mapped[bool] = mapped_column(
+        Boolean,
+        default=False,
+        nullable=False,
+        comment="是否已完成",
+    )
+    progress_percent: Mapped[float] = mapped_column(
+        Float,
+        default=0.0,
+        nullable=False,
+        comment="阅读/播放进度百分比(0-100)",
+    )
+    
+    # 视频/音频特有字段
+    last_position: Mapped[int] = mapped_column(
+        Integer,
+        default=0,
+        nullable=False,
+        comment="上次播放位置(秒)",
+    )
+    total_duration: Mapped[int] = mapped_column(
+        Integer,
+        default=0,
+        nullable=False,
+        comment="媒体总时长(秒)",
+    )
+    
+    # 学习时长
+    study_time: Mapped[int] = mapped_column(
+        Integer,
+        default=0,
+        nullable=False,
+        comment="学习时长(秒)",
+    )
+    
+    # 时间记录
+    first_accessed_at: Mapped[Optional[datetime]] = mapped_column(
+        DateTime,
+        nullable=True,
+        comment="首次访问时间",
+    )
+    last_accessed_at: Mapped[Optional[datetime]] = mapped_column(
+        DateTime,
+        nullable=True,
+        comment="最后访问时间",
+    )
+    completed_at: Mapped[Optional[datetime]] = mapped_column(
+        DateTime,
+        nullable=True,
+        comment="完成时间",
+    )
+    
+    # 关联关系
+    user = relationship("User", backref="material_progress")
+    material = relationship("CourseMaterial", backref="user_progress")
+    course = relationship("Course", backref="material_user_progress")