feat: KPL v1.5.0 功能迭代

1. 奖章条件优化
- 修复统计查询 SQL 语法
- 添加按类别检查奖章方法

2. 移动端适配
- 登录页、课程中心、课程详情
- 考试页面、成长路径、排行榜

3. 证书系统
- 数据库模型和迁移脚本
- 证书颁发/列表/下载/验证 API
- 前端证书列表页面

4. 数据大屏
- 企业级/团队级数据 API
- ECharts 可视化大屏页面

backend/app/models/__init__.py

@@ -27,6 +27,11 @@ from app.models.level import (
     BadgeCategory,
     ConditionType,
 )
+from app.models.certificate import (
+    CertificateTemplate,
+    UserCertificate,
+    CertificateType,
+)
 
 __all__ = [
     "Base",
@@ -64,4 +69,7 @@ __all__ = [
     "ExpType",
     "BadgeCategory",
     "ConditionType",
+    "CertificateTemplate",
+    "UserCertificate",
+    "CertificateType",
 ]

backend/app/models/certificate.py

@@ -0,0 +1,76 @@
+"""
+证书系统数据模型
+
+定义证书模板和用户证书的数据结构
+"""
+
+from datetime import datetime
+from enum import Enum
+from typing import Optional
+from sqlalchemy import Column, Integer, String, Text, Boolean, DateTime, ForeignKey, Enum as SQLEnum, DECIMAL, JSON
+from sqlalchemy.orm import relationship
+
+from app.core.database import Base
+
+
+class CertificateType(str, Enum):
+    """证书类型枚举"""
+    COURSE = "course"           # 课程结业证书
+    EXAM = "exam"               # 考试合格证书
+    ACHIEVEMENT = "achievement"  # 成就证书
+
+
+class CertificateTemplate(Base):
+    """证书模板表"""
+    __tablename__ = "certificate_templates"
+    
+    id = Column(Integer, primary_key=True, autoincrement=True)
+    name = Column(String(100), nullable=False, comment="模板名称")
+    type = Column(SQLEnum(CertificateType), nullable=False, comment="证书类型")
+    background_url = Column(String(500), comment="证书背景图URL")
+    template_html = Column(Text, comment="HTML模板内容")
+    template_style = Column(Text, comment="CSS样式")
+    is_active = Column(Boolean, default=True, comment="是否启用")
+    sort_order = Column(Integer, default=0, comment="排序顺序")
+    created_at = Column(DateTime, nullable=False, default=datetime.now)
+    updated_at = Column(DateTime, nullable=False, default=datetime.now, onupdate=datetime.now)
+    
+    # 关联
+    certificates = relationship("UserCertificate", back_populates="template")
+
+
+class UserCertificate(Base):
+    """用户证书表"""
+    __tablename__ = "user_certificates"
+    
+    id = Column(Integer, primary_key=True, autoincrement=True)
+    user_id = Column(Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False, comment="用户ID")
+    template_id = Column(Integer, ForeignKey("certificate_templates.id"), nullable=False, comment="模板ID")
+    certificate_no = Column(String(50), unique=True, nullable=False, comment="证书编号")
+    title = Column(String(200), nullable=False, comment="证书标题")
+    description = Column(Text, comment="证书描述")
+    issued_at = Column(DateTime, default=datetime.now, comment="颁发时间")
+    valid_until = Column(DateTime, comment="有效期至")
+    
+    # 关联信息
+    course_id = Column(Integer, comment="关联课程ID")
+    exam_id = Column(Integer, comment="关联考试ID")
+    badge_id = Column(Integer, comment="关联奖章ID")
+    
+    # 成绩信息
+    score = Column(DECIMAL(5, 2), comment="考试分数")
+    completion_rate = Column(DECIMAL(5, 2), comment="完成率")
+    
+    # 生成的文件
+    pdf_url = Column(String(500), comment="PDF文件URL")
+    image_url = Column(String(500), comment="分享图片URL")
+    
+    # 元数据
+    meta_data = Column(JSON, comment="扩展元数据")
+    
+    created_at = Column(DateTime, nullable=False, default=datetime.now)
+    updated_at = Column(DateTime, nullable=False, default=datetime.now, onupdate=datetime.now)
+    
+    # 关联
+    template = relationship("CertificateTemplate", back_populates="certificates")
+    user = relationship("User", backref="certificates")