feat: integrate emoji-mart and refactor emoji usage

- Added @emoji-mart/data and @emoji-mart/react dependencies for enhanced emoji support.
- Replaced static emoji characters with Emoji component in various UI components for consistency and improved rendering.
- Updated generateDateTitle function to return an object with emoji and text for better structure.
- Marked the task for removing emojis from the UI as complete in TODO.md.

src/lib/avatars.ts

@@ -123,3 +123,4 @@ export function validateCustomAvatarUrl(url: string): boolean {
     return false
   }
 }
+