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/services/mootdx.py

@@ -3,7 +3,6 @@
 通过 TCP 协议直连通达信行情服务器，不走 HTTP，不会被限流。
 主要用途：
 - K线数据：主数据源（稳定可靠）
-- 板块数据：东方财富 push2 的降级方案
 """
 
 import asyncio
@@ -69,60 +68,3 @@ async def fetch_kline_history(code: str, days: int = 90) -> Optional[List[dict]]
     except Exception as e:
         print(f"[mootdx] fetch_kline error: {e}")
         return None
-
-
-# ---- 板块数据（东方财富降级方案）----
-
-
-def _sync_fetch_sectors(sector_type: str) -> Optional[list]:
-    from mootdx.consts import MARKET_SH, MARKET_SZ
-
-    client = _create_client()
-
-    # block() 返回 DataFrame，列：code, name 等
-    # 按板块类型过滤
-    block_df = client.block()
-    if block_df is None or block_df.empty:
-        return None
-
-    items = []
-    for _, row in block_df.iterrows():
-        name = str(row.get("name", "") or row.get("blockname", ""))
-        code = str(row.get("code", "") or row.get("blockcode", ""))
-        if not code or not name:
-            continue
-
-        items.append(
-            {
-                "code": code,
-                "name": name,
-                "level": None,
-                "changePercent": None,
-                "changeAmount": None,
-                "mainNetInflow": 0,
-                "mainNetInflowPercent": None,
-                "superLargeInflow": None,
-                "superLargeInflowPercent": None,
-                "largeInflow": None,
-                "largeInflowPercent": None,
-                "mediumInflow": None,
-                "mediumInflowPercent": None,
-                "smallInflow": None,
-                "smallInflowPercent": None,
-                "turnover": 0,
-            }
-        )
-
-    return items if items else None
-
-
-async def fetch_sector_list(sector_type: str) -> Optional[List[dict]]:
-    """获取板块列表（东方财富的降级方案，仅含代码和名称）"""
-    try:
-        loop = asyncio.get_event_loop()
-        return await loop.run_in_executor(None, _sync_fetch_sectors, sector_type)
-    except ImportError:
-        return None
-    except Exception as e:
-        print(f"[mootdx] fetch_sectors error: {e}")
-        return None