fix: Add type="button" to tab buttons to prevent form submission

Critical bug: Tab buttons were submitting the form

Problem:
- Buttons inside <form> default to type="submit"
- Clicking any tab triggered form submission
- Form would submit instead of switching tabs
- Very disruptive UX

Fix:
- Added type="button" to all tab buttons
- Mobile horizontal tabs
- Desktop vertical tabs
- Now tabs only switch sections, no submit

Changes:
1. Mobile tab buttons: type="button"
2. Desktop tab buttons: type="button"

Result:
✅ Tabs switch sections without submitting
✅ Form only submits via submit button
✅ Proper form behavior

admin-spa/src/routes/Products/index.tsx

@@ -379,7 +379,7 @@ export default function Products() {
                             <Package className="w-5 h-5 text-muted-foreground" />
                           </div>
                         )}
-                        <Link to={`/products/${product.id}`} className="font-medium hover:underline">
+                        <Link to={`/products/${product.id}/edit`} className="font-medium hover:underline">
                           {product.name}
                         </Link>
                       </div>