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/api/v1/feedback.py

@@ -0,0 +1,35 @@
+from fastapi import APIRouter, Depends, HTTPException
+from sqlalchemy.ext.asyncio import AsyncSession
+from typing import Annotated
+from pydantic import BaseModel
+from app.database import get_db
+from app.models.feedback import Feedback
+from app.api.v1.deps import get_current_user_id
+
+router = APIRouter()
+
+
+class FeedbackRequest(BaseModel):
+    category: str = "general"
+    content: str
+    contact: str = ""
+
+
+@router.post("")
+async def submit_feedback(
+    data: FeedbackRequest,
+    user_id: str = Depends(get_current_user_id),
+    db: Annotated[AsyncSession, Depends(get_db)] = None,
+):
+    if not data.content.strip():
+        raise HTTPException(status_code=400, detail="Content is required")
+
+    fb = Feedback(
+        user_id=user_id,
+        category=data.category,
+        content=data.content.strip(),
+        contact=data.contact.strip(),
+    )
+    db.add(fb)
+    await db.flush()
+    return {"status": "ok", "id": str(fb.id)}