feat: enable author info in reply screen post preview

Add author information to reply screen for consistency with detail view:

- Enable showAuthorFooter in PostCard configuration
- Shows author handle and timestamp above post title
- Provides context about who created the original post
- Maintains same enhanced typography as detail view

This ensures users see clear attribution when composing replies,
matching the enhanced information hierarchy of the detail view.

Changes:
- Set showAuthorFooter: true in PostCard configuration
- Matches detail view settings: 20px title, 16px text, 280px embeds

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Changed files
+7
lib
screens
+7
lib/screens/compose/reply_screen.dart
···
disableNavigation: true,
showActions: false,
showBorder: false,
+
showFullText: true,
+
showAuthorFooter: true,
+
textFontSize: 16,
+
textLineHeight: 1.6,
+
embedHeight: 280,
+
titleFontSize: 20,
+
titleFontWeight: FontWeight.w600,
);
},
);