重构项目结构，删除未使用的组件和文件，添加主页和模态页实现

docs/architecture.md

@@ -14,9 +14,13 @@ This project uses Expo Router and follows a route-first + feature-module structu
 ## Current Module Split
 
 - `app/_layout.tsx`
-  - Root navigation composition only.
+  - Root navigation composition.
   - Theme provider and route stack config.
-  - No SDK side effects.
+  - App bootstrap provider wiring.
+
+- `app/index.tsx` and `app/modal.tsx`
+  - Route shells only.
+  - Delegate screen implementation to `features/*/screens`.
 
 - `providers/app-bootstrap-provider.tsx`
   - Central app bootstrap orchestration.
@@ -30,6 +34,12 @@ This project uses Expo Router and follows a route-first + feature-module structu
 - `features/im/hooks/use-openim-bootstrap.ts`
   - React lifecycle bridge for IM bootstrap.
 
+- `features/home/screens/home-screen.tsx`
+  - Home page UI implementation.
+
+- `features/system/screens/modal-screen.tsx`
+  - Modal page UI implementation.
+
 ## Why This Structure
 
 - Keeps routing files focused on navigation.
@@ -41,4 +51,4 @@ This project uses Expo Router and follows a route-first + feature-module structu
 
 1. Move IM API wrappers into `features/im/services/`.
 2. Add `features/chat/hooks/use-chat-list.ts` and `features/chat/hooks/use-messages.ts`.
-3. Keep `app/(tabs)` as route shells and move business UI into `features/*/screens`.
+3. Add route groups when chat modules are introduced, for example `app/(chat)` and `app/(auth)`.