Refactor SwipeTabs for smoother touch transitions

- Rewrite SwipeTabs with improved touch handling and animation
- Use translate3d with smoother easing curve (280ms)
- Add coalesced pointer events for high refresh rate displays
- Clean up redundant CSS styles across multiple files
- Add page-max-width dimension variable

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/styles/theme/dimensions.css

@@ -61,6 +61,8 @@
   --page-padding-y-mobile: 1.25rem;
   --page-max-width: 1200px;
   /* Maximum content width */
+  --page-max-width-narrow: 800px;
+  /* Narrow content width */
 
   /* Container Widths */
   --container-sm: 640px;