feat(content): add rich content rendering with @mentions and vote segments

- Add PostContentRenderer component for rendering posts/comments with segments
- Add PostMentionInput component for @mention support in post/comment creation
- Add VoteSegmentData and vote segment type for unified post creation API
- Update post and comment services to support segments in API requests
- Fix auth service to clear tokens before login/register
- Improve database initialization with proper close/retry logic
- Add verification check before allowing post creation
- Add metro web shims for react-native-webrtc full package and requireNativeComponent
- Update build config with git hash based version numbers

src/components/business/index.ts

@@ -22,5 +22,7 @@ export { default as TabBar } from './TabBar';
 export { default as VoteCard } from './VoteCard';
 export { default as VoteEditor } from './VoteEditor';
 export { default as VotePreview } from './VotePreview';
+export { default as PostContentRenderer } from './PostContentRenderer';
+export { default as PostMentionInput } from './PostMentionInput';
 export { default as ReportDialog } from './ReportDialog';
 export { default as ShareSheet } from './ShareSheet';