refactor(stores): reorganize flat store files into modular directory structure

Migrate from flat file organization to modular directory structure under src/stores/:

- auth/: authStore, registerStore, verificationStore, sessionStore
- call/: callStore
- settings/: chatSettingsStore, themeStore
- ui/: homeTabBarVisibilityStore, homeTabPressStore
- utils/: routePayloadCache
- group/sources.ts, group/profileResolver.ts
- message/sources.ts
- post/sources.ts

Update all import paths across components and screens to use new module paths. Maintain backward compatibility through deprecated re-export files for gradual migration.

src/stores/ui/homeTabBarVisibilityStore.ts

@@ -0,0 +1,12 @@
+import { create } from 'zustand';
+
+interface HomeTabBarVisibilityState {
+  /** 首页列表下滑时隐藏底部 Tab，上滑或闲置后恢复 */
+  bottomTabBarHiddenByScroll: boolean;
+  setBottomTabBarHiddenByScroll: (hidden: boolean) => void;
+}
+
+export const useHomeTabBarVisibilityStore = create<HomeTabBarVisibilityState>((set) => ({
+  bottomTabBarHiddenByScroll: false,
+  setBottomTabBarHiddenByScroll: (hidden) => set({ bottomTabBarHiddenByScroll: hidden }),
+}));

src/stores/ui/homeTabPressStore.ts

@@ -0,0 +1,13 @@
+import { create } from 'zustand';
+
+interface HomeTabPressState {
+  /** 用于触发首页回到顶部的事件计数器 */
+  pressCount: number;
+  /** 触发首页 Tab 点击事件 */
+  triggerPress: () => void;
+}
+
+export const useHomeTabPressStore = create<HomeTabPressState>((set) => ({
+  pressCount: 0,
+  triggerPress: () => set((state) => ({ pressCount: state.pressCount + 1 })),
+}));

src/stores/ui/index.ts

@@ -0,0 +1,6 @@
+/**
+ * UI 状态模块统一导出
+ */
+
+export { useHomeTabBarVisibilityStore } from './homeTabBarVisibilityStore';
+export { useHomeTabPressStore } from './homeTabPressStore';