refactor(mp): 架构重构 — usePageData 统一数据加载 + Store 解耦 + 大页面拆分

新增 usePageData hook（useDidShow 节流 + usePullDownRefresh + loadingRef 防重入 + enabled 条件守卫），
44/58 页面迁移接入，消灭 4 种数据加载模式并存。

- 新增 hooks/usePageData.ts — 统一页面数据加载生命周期
- 新增 stores/index.ts — resetAllStores() 解耦 auth↔health store 依赖
- 新增 pages/index/useHomeData.ts — 首页数据 hook（424→282 行）
- 新增 pages/health/useHealthData.ts — 健康页数据 hook（422→254 行）
- 44 个页面迁移到 usePageData（9 患者端 + 15 医生端 + 20 子包）
- auth store logout 不再直接导入 health store

构建通过，测试 74/75（1 个预存失败）。

apps/miniprogram/src/hooks/usePageData.ts

@@ -0,0 +1,70 @@
+import { useRef, useCallback } from 'react';
+import Taro, { useDidShow, usePullDownRefresh } from '@tarojs/taro';
+
+interface UsePageDataOptions {
+  throttleMs?: number;
+  enablePullDown?: boolean;
+  enabled?: boolean;
+}
+
+interface UsePageDataResult {
+  loading: boolean;
+  refresh: () => Promise<void>;
+  trigger: () => void;
+}
+
+export function usePageData(
+  fetcher: () => Promise<void>,
+  options?: UsePageDataOptions,
+): UsePageDataResult {
+  const throttleMs = options?.throttleMs ?? 5000;
+  const enablePullDown = options?.enablePullDown ?? false;
+  const enabled = options?.enabled ?? true;
+
+  const loadingRef = useRef(false);
+  const lastRunRef = useRef(0);
+  const fetcherRef = useRef(fetcher);
+  fetcherRef.current = fetcher;
+
+  const run = useCallback(async (force = false) => {
+    if (!enabled || loadingRef.current) return;
+    if (!force && Date.now() - lastRunRef.current < throttleMs) return;
+    loadingRef.current = true;
+    lastRunRef.current = Date.now();
+    try {
+      await fetcherRef.current();
+    } finally {
+      loadingRef.current = false;
+    }
+  }, [enabled, throttleMs]);
+
+  useDidShow(() => {
+    run();
+  });
+
+  const trigger = useCallback(() => {
+    run(true);
+  }, [run]);
+
+  const refresh = useCallback(async () => {
+    if (loadingRef.current) return;
+    loadingRef.current = true;
+    lastRunRef.current = Date.now();
+    try {
+      await fetcherRef.current();
+    } finally {
+      loadingRef.current = false;
+    }
+  }, []);
+
+  usePullDownRefresh(async () => {
+    if (!enablePullDown) return;
+    try {
+      await refresh();
+    } finally {
+      Taro.stopPullDownRefresh();
+    }
+  });
+
+  return { loading: loadingRef.current, refresh, trigger };
+}