fix: Always show price selection modal and use browser for JS-heavy sites

- Always show price selection modal when adding a product so users can verify
- Use browser rendering for known JS-heavy sites (Best Buy, Target, Walmart, Costco)
- Update modal text to say "Confirm Price" for single candidates

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

frontend/src/components/PriceSelectionModal.tsx

@@ -265,9 +265,13 @@ export default function PriceSelectionModal({
 
       <div className="price-modal">
         <div className="price-modal-header">
-          <h2 className="price-modal-title">Multiple Prices Found</h2>
+          <h2 className="price-modal-title">
+            {candidates.length > 1 ? 'Multiple Prices Found' : 'Confirm Price'}
+          </h2>
           <p className="price-modal-subtitle">
-            We found different prices for this product. Please select the correct one.
+            {candidates.length > 1
+              ? 'We found different prices for this product. Please select the correct one.'
+              : 'Please verify this is the correct price for the product.'}
           </p>
         </div>