feat: improve mobile responsiveness across UI components

- Add responsive layout for action buttons (stack vertically on mobile, horizontal on sm+)
- Adjust card max-widths for better mobile display (LocationCard, MultiBillEdit)
- Improve button text sizing with responsive classes (text-sm on mobile, text-xs on sm+)
- Remove width constraints on file inputs and info boxes for full-width mobile layout
- Fine-tune icon positioning for better visual alignment

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

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

app/ui/BillEditForm.tsx

@@ -147,7 +147,7 @@ export const BillEditForm: FC<BillEditFormProps> = ({ location, bill }) => {
                             : null
                     }
                     <div className="flex">
-                        <input id="billAttachment" name="billAttachment" type="file" className="file-input file-input-bordered grow file-input-s my-2 block max-w-[17em] md:max-w-[80em] break-words" onChange={billAttachment_handleChange} />
+                        <input id="billAttachment" name="billAttachment" type="file" className="file-input file-input-bordered grow file-input-s my-2 block w-full break-words" onChange={billAttachment_handleChange} />
                     </div>
                     {
                         isScanningPDF &&