feat: add reports center, admin drill-down, disease filter + bug fixes + perf optimization

Frontend features:
- 报表中心 (ReportsCenter): list/detail views, diagnosis breakdown chart, CSV export
- 多级行政下钻 (AdminBreadcrumb): 湖北省→武汉市→区→街道 hierarchical drill-down
- 按病种筛选 (DiseaseFilter): multi-select diagnosis filter on monitoring + reports pages

Backend:
- Add /forecast/{days} endpoint, diagnosis filter params on cases endpoints
- Add /streets aggregation endpoint, enrich reports with real case data
- Extract shared case_loader module

Bug fixes (14):
- Fix missing /risk/forecast route (404), historyApi pointing to non-existent router
- Fix min_risk filter silently ignored in insights/hotspots
- Fix type mismatches: CaseTrendResponse, CaseStatsResponse shapes
- Fix silent .catch(() => {}) swallowing errors, fetchAlerts not clearing stale state
- Fix lru_cache caching exceptions, generateReport used cachedGet for write op
- Fix missing useEffect deps in Insights, DistrictComparison, ReportsCenter

Performance (9):
- Zustand selectors across 9 components (eliminate re-render cascades)
- Fix districtCases.sort() mutating store state, inline IIFE → memo'd component
- CaseLocationMap: React.memo, race protection, correct deps
- AlertCard: stable callbacks, TimelinePlayer: useMemo, TopNav: clock isolation
- SideNav: modules array to module scope, DiseaseFilter: memoized filter

frontend/src/components/CaseLocationMap.tsx

@@ -1,27 +1,30 @@
-import { useEffect, useRef, useState } from 'react';
+import { useEffect, useRef, useState, memo } from 'react';
 import L from 'leaflet';
-
-interface CaseLocation {
-  case_id: string;
-  case_type: string;
-  latitude: number;
-  longitude: number;
-  district: string;
-  street: string;
-}
+import { geocodedApi } from '@/services/api';
+import type { GeocodedCase } from '@/types';
 
 const WUHAN_CENTER: [number, number] = [30.59, 114.31];
 
-export function CaseLocationMap({ height = '400px' }: { height?: string }) {
+interface CaseLocationMapProps {
+  height?: string;
+  district?: string | null;
+  street?: string | null;
+}
+
+function CaseLocationMapComponent({ height = '400px', district = null, street = null }: CaseLocationMapProps) {
   const mapRef = useRef<HTMLDivElement>(null);
   const mapInstanceRef = useRef<L.Map | null>(null);
   const layerRef = useRef<L.LayerGroup | null>(null);
+  const cancelledRef = useRef(false);
   const [isLoading, setIsLoading] = useState(true);
   const [caseCount, setCaseCount] = useState(0);
 
   useEffect(() => {
     if (!mapRef.current || mapInstanceRef.current) return;
 
+    setIsLoading(true);
+    cancelledRef.current = false;
+
     const map = L.map(mapRef.current, {
       center: WUHAN_CENTER,
       zoom: 11,
@@ -37,10 +40,10 @@ export function CaseLocationMap({ height = '400px' }: { height?: string }) {
     layerRef.current = L.layerGroup().addTo(map);
 
     // Fetch case locations
-    fetch('/api/geocoded/geocoded?limit=5000')
-      .then((res) => res.json())
+    geocodedApi.getGeocoded({ limit: 5000, district: district || undefined })
       .then((data) => {
-        const cases: CaseLocation[] = data.cases || [];
+        if (cancelledRef.current) return;
+        const cases: GeocodedCase[] = data.cases || [];
         const layer = layerRef.current;
         if (!layer) return;
 
@@ -48,7 +51,7 @@ export function CaseLocationMap({ height = '400px' }: { height?: string }) {
 
         // Deduplicate by case_id to avoid overlapping markers
         const seen = new Set<string>();
-        const unique: CaseLocation[] = [];
+        let unique: GeocodedCase[] = [];
         for (const c of cases) {
           if (!seen.has(c.case_id)) {
             seen.add(c.case_id);
@@ -56,6 +59,13 @@ export function CaseLocationMap({ height = '400px' }: { height?: string }) {
           }
         }
 
+        // Client-side street filtering
+        if (street) {
+          unique = unique.filter((c) => c.street === street);
+        }
+
+        if (cancelledRef.current) return;
+
         for (const c of unique) {
           if (!c.latitude || !c.longitude) continue;
 
@@ -88,13 +98,16 @@ export function CaseLocationMap({ height = '400px' }: { height?: string }) {
           map.fitBounds(bounds, { padding: [30, 30] });
         }
       })
-      .catch(() => setIsLoading(false));
+      .catch(() => {
+        if (!cancelledRef.current) setIsLoading(false);
+      });
 
     return () => {
+      cancelledRef.current = true;
       map.remove();
       mapInstanceRef.current = null;
     };
-  }, []);
+  }, [district, street]);
 
   return (
     <div className="relative">
@@ -114,3 +127,5 @@ export function CaseLocationMap({ height = '400px' }: { height?: string }) {
     </div>
   );
 }
+
+export const CaseLocationMap = memo(CaseLocationMapComponent);