feat: 修复 H5 底部导航覆盖 + 更新项目进度文档

## H5 底部导航修复 (Bug #10)
- 精简 App.vue，移除重复 tabbar，仅保留全局样式
- uni-page 设置 height: calc(100% - 50px) + overflow-y: auto
- 内容区域精确停在底部导航上方，独立滚动不再叠加
- 恢复 custom-tab-bar 组件

## 项目进度文档
- PROGRESS.md 更新至 10 个 Bug 修复
- 新增 H5 底部导航修复记录
- 新增历史变更条目

backend/app/models/user.py

@@ -1,4 +1,4 @@
-from sqlalchemy import Column, String, Boolean, Integer, DateTime, Text
+from sqlalchemy import Column, String, Boolean, Integer, DateTime, Text, ForeignKey
 from sqlalchemy.dialects.postgresql import UUID, JSONB
 from sqlalchemy.orm import relationship
 from datetime import datetime
@@ -15,6 +15,7 @@ class User(Base):
     username = Column(String(100))
     password_hash = Column(String(255))
     tier = Column(String(50), default="free")
+    role = Column(String(20), default="user")
     is_active = Column(Boolean, default=True)
     created_at = Column(DateTime, default=datetime.utcnow)
     updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
@@ -35,7 +36,7 @@ class Product(Base):
     __tablename__ = "products"
 
     id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
-    user_id = Column(UUID(as_uuid=True), nullable=False, index=True)
+    user_id = Column(UUID(as_uuid=True), ForeignKey("users.id"), nullable=False, index=True)
     name = Column(String(255), nullable=False)
     name_en = Column(String(255))
     description = Column(Text)