Fix multilingual routing for virtual product pages

Use site()->visit() to properly set language context for virtual pages.
This ensures UI translations and language-specific content work correctly
on both /slug (French) and /en/slug (English) routes.

Changes:
- Add site()->visit($page, $lang) in routes to set page language
- Create product controller for language detection
- Fix add-to-cart button to update text in .txt div instead of button
- Remove broken hooks approach

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

assets/js/product-add-to-cart.js

@@ -10,6 +10,13 @@
     return;
   }
 
+  const buttonTextDiv = addToCartBtn.querySelector('.txt[data-button-text]');
+
+  if (!buttonTextDiv) {
+    console.error('Button text div not found');
+    return;
+  }
+
   const texts = {
     add: addToCartBtn.dataset.textAdd || 'Add to cart',
     adding: addToCartBtn.dataset.textAdding || 'Adding...',
@@ -28,13 +35,13 @@
     }
 
     addToCartBtn.disabled = true;
-    const originalText = addToCartBtn.textContent;
-    addToCartBtn.textContent = texts.adding;
+    const originalText = buttonTextDiv.textContent;
+    buttonTextDiv.textContent = texts.adding;
 
     try {
       const cartResult = await cart.addToCart(variantId, 1);
 
-      addToCartBtn.textContent = texts.added;
+      buttonTextDiv.textContent = texts.added;
       addToCartBtn.classList.add('success');
 
       document.dispatchEvent(new CustomEvent('cart:updated', {
@@ -43,19 +50,19 @@
 
       setTimeout(() => {
         addToCartBtn.disabled = false;
-        addToCartBtn.textContent = originalText;
+        buttonTextDiv.textContent = originalText;
         addToCartBtn.classList.remove('success');
       }, 1500);
 
     } catch (error) {
       console.error('Error adding to cart:', error);
 
-      addToCartBtn.textContent = texts.error;
+      buttonTextDiv.textContent = texts.error;
       addToCartBtn.classList.add('error');
 
       setTimeout(() => {
         addToCartBtn.disabled = false;
-        addToCartBtn.textContent = originalText;
+        buttonTextDiv.textContent = originalText;
         addToCartBtn.classList.remove('error');
       }, 2000);
     }