fix(scope): all pages react to company scope change via useScopeEffect

- Created useScopeEffect hook that auto-triggers reload on scope change
- Replaced useEffect([], []) with useScopeEffect in 20+ pages
- Risks/Reports/Dashboard also use useScopeEffect
- Removed redundant per-page useCompanyScope where only effect was needed

frontend/src/app/(investor)/sentinels/page.tsx

@@ -1,6 +1,7 @@
 "use client";
 
-import { useEffect, useState } from "react";
+import { useState } from "react";
+import { useScopeEffect } from "@/lib/company-scope";
 import { listDecisionSentinels } from "@/lib/api-v2";
 import { PageContainer, Badge} from "@/components/shared/PageContainer";
 import { LoadingSpinner } from "@/components/shared/LoadingSpinner";
@@ -18,12 +19,12 @@ export default function SentinelsPage() {
   const [items, setItems] = useState<DecisionSentinel[]>([]);
   const [isLoading, setIsLoading] = useState(true);
 
-  useEffect(() => {
+  useScopeEffect(() => {
     listDecisionSentinels()
       .then((resp) => setItems((resp.data as DecisionSentinel[]) ?? []))
       .catch(() => setItems([]))
       .finally(() => setIsLoading(false));
-  }, []);
+  });
 
   return (
     <PageContainer title="决策前哨" description="AI 识别关键决策岔路口 → 场景分析 → 提前预警">