feat: 题材列表盘中120s缓存共用，题材详情新增全量新闻分页+强度热度行情

- 题材热点与热点穿透共用题材列表缓存：盘中由"不缓存实时拉取"改为120s短缓存，
  东财全量列表拉取降到每120s一次，图重建时涨幅/热度两榜直接命中缓存
- 详情页相关新闻升级为全量分页(getThemeRelatedNews)：支持翻页+评论数，
  替换原 getDetail 固定3条
- 详情页统计条新增强度+热度(getSingleThemeQuote)实时指标

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

backend/routes/themes.py

@@ -52,6 +52,39 @@ async def theme_history(date: str = Query(..., description="交易日 YYYY-MM-DD
         conn.close()
 
 
+@router.get("/{theme_code}/news", summary="题材相关新闻（分页）")
+async def theme_news(
+    theme_code: str,
+    page_num: int = Query(1, ge=1, description="页码"),
+    page_size: int = Query(10, ge=1, le=50, description="每页条数"),
+    max_eu_time: str = Query("", description="分页游标（上一页返回的 maxEuTime）"),
+):
+    result = await themes.fetch_theme_news(theme_code, page_num, max_eu_time, page_size)
+    if result is None:
+        return JSONResponse(
+            {"data": None, "theme_code": theme_code},
+            headers=_NO_CACHE_HEADERS,
+        )
+    return JSONResponse(
+        {"data": result, "theme_code": theme_code},
+        headers=_NO_CACHE_HEADERS,
+    )
+
+
+@router.get("/{theme_code}/quote", summary="单题材实时行情（强度/热度/涨幅）")
+async def theme_quote(theme_code: str):
+    result = await themes.fetch_theme_quote(theme_code)
+    if result is None:
+        return JSONResponse(
+            {"data": None, "theme_code": theme_code},
+            headers=_NO_CACHE_HEADERS,
+        )
+    return JSONResponse(
+        {"data": result, "theme_code": theme_code},
+        headers=_NO_CACHE_HEADERS,
+    )
+
+
 @router.get("/{theme_code}/detail", summary="题材详情")
 async def theme_detail(theme_code: str):
     data = await themes.fetch_theme_detail(theme_code)