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/team.py

@@ -0,0 +1,38 @@
+from sqlalchemy import Column, String, Boolean, DateTime, ForeignKey, Text, Integer
+from sqlalchemy.dialects.postgresql import UUID, JSONB
+from sqlalchemy.orm import relationship
+from datetime import datetime
+from app.database import Base
+import uuid
+
+
+class Team(Base):
+    __tablename__ = "teams"
+
+    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
+    name = Column(String(255), nullable=False)
+    owner_id = Column(UUID(as_uuid=True), nullable=False, index=True)
+    description = Column(Text)
+    member_count = Column(Integer, default=0)
+    max_members = Column(Integer, default=5)
+    tier = Column(String(50), default="free")
+    is_active = Column(Boolean, default=True)
+    created_at = Column(DateTime, default=datetime.utcnow)
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
+
+    members = relationship("TeamMember", back_populates="team", cascade="all, delete-orphan")
+
+
+class TeamMember(Base):
+    __tablename__ = "team_members"
+
+    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
+    team_id = Column(UUID(as_uuid=True), ForeignKey("teams.id"), nullable=False, index=True)
+    user_id = Column(UUID(as_uuid=True), nullable=False, index=True)
+    role = Column(String(50), default="member")
+    invited_by = Column(UUID(as_uuid=True))
+    status = Column(String(50), default="active")
+    joined_at = Column(DateTime, default=datetime.utcnow)
+    created_at = Column(DateTime, default=datetime.utcnow)
+
+    team = relationship("Team", back_populates="members")