Add product review model, serializer, and API endpoint

Introduces a Review model for product reviews, including rating and comment fields. Adds a public serializer and a ModelViewSet for reviews with search and ordering capabilities. Also updates the frontend API client to use the correct token refresh endpoint and improves FormData handling.

backend/commerce/models.py

@@ -616,4 +616,22 @@ class Invoice(models.Model):
 
         # Save directly to FileField
         self.pdf_file.save(f"{self.invoice_number}.pdf", ContentFile(pdf_bytes))
-        self.save()
+        self.save()
+
+
+class Review(models.Model):
+    product = models.ForeignKey(Product, related_name="reviews", on_delete=models.CASCADE)
+    user = models.ForeignKey(
+        settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="reviews"
+    )
+    
+    rating = models.PositiveIntegerField(
+        validators=[MinValueValidator(1), MaxValueValidator(5)]
+    )
+    comment = models.TextField(blank=True)
+
+    created_at = models.DateTimeField(auto_now_add=True)
+    updated_at = models.DateTimeField(auto_now=True)
+
+    def __str__(self):
+        return f"Review for {self.product.name} by {self.user.username}"