feat: NEXT Store 2.0 重大更新 - 完整重构前后端

🎉 主要更新:

后端:
- 全新华为应用市场爬虫系统
- 三表分离数据库设计 (app_info, app_metrics, app_rating)
- 完整的API接口 (搜索、分类、热门、上新等)
- 元服务自动识别和分类
- 智能Token管理和数据处理
- 修复热门应用重复显示问题

前端:
- 全新首页设计 (今日上架、热门应用)
- 应用页面 (彩色分类磁贴、智能图标匹配)
- 今日上新页面 (日期切换)
- 热门应用页面 (卡片布局)
- 应用详情页面 (完整信息展示)
- Apple风格搜索栏
- Footer组件
- 底部导航栏优化 (4个导航项)
- 骨架屏加载效果
- FontAwesome图标集成

UI/UX:
- 统一浅色背景 (#F5F5F7)
- 流畅的过渡动画
- 响应式设计
- 毛玻璃效果

文档:
- CHANGELOG.md - 完整更新日志
- QUICKSTART.md - 快速开始
- 多个技术文档和使用指南

版本: v2.0.0

backend/migrate_db.py

@@ -0,0 +1,79 @@
+#!/usr/bin/env python3
+"""
+数据库迁移脚本 - 添加新字段
+"""
+import asyncio
+from sqlalchemy import text
+from app.database import engine
+
+
+async def column_exists(conn, table_name: str, column_name: str) -> bool:
+    """检查列是否存在"""
+    result = await conn.execute(text(f"""
+        SELECT COUNT(*) 
+        FROM information_schema.COLUMNS 
+        WHERE TABLE_SCHEMA = DATABASE() 
+        AND TABLE_NAME = '{table_name}' 
+        AND COLUMN_NAME = '{column_name}'
+    """))
+    count = result.scalar()
+    return count > 0
+
+
+async def add_column_if_not_exists(conn, table_name: str, column_name: str, column_def: str):
+    """如果列不存在则添加"""
+    if not await column_exists(conn, table_name, column_name):
+        sql = f"ALTER TABLE {table_name} ADD COLUMN {column_name} {column_def}"
+        print(f"添加字段: {column_name}...")
+        await conn.execute(text(sql))
+        print(f"✓ {column_name} 添加成功")
+    else:
+        print(f"○ {column_name} 已存在，跳过")
+
+
+async def migrate():
+    """添加新字段到 app_info 表"""
+    print("=" * 60)
+    print("开始数据库迁移...")
+    print("=" * 60)
+    
+    migrations = [
+        # (列名, 列定义)
+        ("dev_id", "VARCHAR(100)"),
+        ("supplier", "VARCHAR(255)"),
+        ("kind_id", "VARCHAR(50)"),
+        ("tag_name", "VARCHAR(100)"),
+        ("price", "VARCHAR(50) DEFAULT '0'"),
+        ("main_device_codes", "JSON"),
+        ("target_sdk", "VARCHAR(50)"),
+        ("min_sdk", "VARCHAR(50)"),
+        ("compile_sdk_version", "INT"),
+        ("min_hmos_api_level", "INT"),
+        ("api_release_type", "VARCHAR(50) DEFAULT 'Release'"),
+        ("ctype", "INT"),
+        ("app_level", "INT"),
+        ("packing_type", "INT"),
+    ]
+    
+    async with engine.begin() as conn:
+        for column_name, column_def in migrations:
+            try:
+                await add_column_if_not_exists(conn, "app_info", column_name, column_def)
+            except Exception as e:
+                print(f"✗ {column_name} 失败: {e}")
+    
+    print("\n" + "=" * 60)
+    print("数据库迁移完成！")
+    print("=" * 60)
+
+
+async def run_migration():
+    """运行迁移并清理"""
+    try:
+        await migrate()
+    finally:
+        await engine.dispose()
+
+
+if __name__ == "__main__":
+    asyncio.run(run_migration())