refactor: 删除板块资金流向，题材板块功能更全

- 删除前端 /sectors 页面、首页入口按钮、stock-api 板块类型与 fetchSectors
- 删除后端 /api/sectors 路由，main.py 移除注册
- eastmoney.py 移除板块数据段(_fetch_push2/_fetch_akshare/UT令牌管理)，
  清理重复 import 与无用 datetime 子导入
- mootdx.py 移除板块降级方案(fetch_sector_list)
- routeTree.gen.ts 由 build 自动重新生成，移除 sectors 路由

题材热点/热点穿透/核心股已覆盖板块能力，功能更全，板块资金流向不再需要

Co-Authored-By: Claude <noreply@anthropic.com>

backend/main.py

@@ -7,7 +7,7 @@ from contextlib import asynccontextmanager
 from dotenv import load_dotenv
 
 from database import init_db
-from routes import stock, collections, shares, sectors, themes, core_stocks
+from routes import stock, collections, shares, themes, core_stocks
 from services.daily_collector import collector_loop, cache_cleanup_loop
 
 load_dotenv()
@@ -43,7 +43,6 @@ app.add_middleware(
 app.include_router(stock.router, prefix="/api/stock")
 app.include_router(collections.router, prefix="/api/collections")
 app.include_router(shares.router, prefix="/api/share")
-app.include_router(sectors.router, prefix="/api/sectors")
 app.include_router(themes.router, prefix="/api/themes")
 app.include_router(core_stocks.router, prefix="/api/core-stocks")