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/services/onboarding.py

@@ -0,0 +1,74 @@
+from typing import Dict, Any, List, Optional
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy import select, func
+from app.models.user import User, Product
+from app.services.marketing import MarketingService
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class OnboardingService:
+    def __init__(self, db: AsyncSession):
+        self.db = db
+
+    async def check_status(self, user_id: str) -> Dict[str, Any]:
+        product_count = await self.db.execute(
+            select(func.count(Product.id)).where(
+                Product.user_id == user_id, Product.is_active == True
+            )
+        )
+        has_products = (product_count.scalar() or 0) > 0
+        return {"onboarded": has_products}
+
+    async def generate_first_product(
+        self, user_id: str, name: str, description: str, category: str = "", target: str = "US importers"
+    ) -> Dict[str, Any]:
+        product = Product(
+            user_id=user_id,
+            name=name,
+            description=description,
+            category=category or "general",
+            is_active=True,
+        )
+        self.db.add(product)
+        await self.db.flush()
+
+        mkt = MarketingService()
+        try:
+            content = await mkt.generate(
+                product_name=name,
+                description=description,
+                category=category or "general",
+                target=target,
+                style="professional",
+                count=3,
+                language="en",
+            )
+        except Exception as e:
+            logger.warning(f"Onboarding content generation failed: {e}")
+            content = [f"Check out our {name} - {description[:100]}..."]
+
+        try:
+            keywords_result = await mkt.generate_keywords(
+                product_name=name, description=description, category=category or "general"
+            )
+            keywords = keywords_result if isinstance(keywords_result, list) else []
+        except Exception as e:
+            logger.warning(f"Keyword generation failed: {e}")
+            keywords = []
+
+        product.keywords = keywords[:10]
+        await self.db.flush()
+
+        return {
+            "product": {
+                "id": str(product.id),
+                "name": product.name,
+                "description": product.description,
+                "category": product.category,
+                "keywords": keywords[:10],
+            },
+            "generated_content": content,
+            "keywords": keywords[:10],
+        }