refactor(post): consolidate post sync to PostSyncService and remove ProcessPostUseCase

- Replace ProcessPostUseCase with new PostSyncService in src/services/post/
- Add postListStore for state management in src/stores/post/
- Remove deprecated ProcessPostUseCase and ProcessMessageUseCase files
- Delete architecture documentation files (ARCHITECTURE_REFACTOR_PLAN.md, architecture-comparison-report.md)
- Update all consumers (HomeScreen, PostDetailScreen, SearchScreen, useUserProfile, useDifferentialPosts)
- Simplify postService to only contain API layer methods
- Remove unused type exports from message stores

BREAKING CHANGE: ProcessPostUseCase and ProcessMessageUseCase have been removed.
Use postSyncService for post operations instead.

src/screens/message/components/ChatScreen/SegmentRenderer.tsx

@@ -862,11 +862,9 @@ function createSegmentStyles(colors: AppColors, fontSize: number = 16) {
   // 容器
   segmentsContainer: {
     flexDirection: 'column',
-    width: '100%',
   },
   segmentsColumn: {
     flexDirection: 'column',
-    width: '100%',
   },
   inlineChunkBase: {
     fontSize,