fix: code quality and safety improvements

Author: Saurabh Kumar Bajpai

frontend/src/components/Ai.jsx

@@ -98,7 +98,8 @@ const USER_QUICK_REPLIES = [
 //       headers: { 'Content-Type': 'application/json' },
 //       body: JSON.stringify({ message }),
 //     });
-//     const data = await res.json();
+//     if (!res.ok) throw new Error("Request failed");
+const data = await res.json();
 //     setIsTyping(false);
 //     speak(data.reply || "Sorry, I couldn't get a response.");
 //   } catch (err) {

frontend/src/pages/Collections.jsx

@@ -80,7 +80,7 @@ const FilterContent = ({
             max={maxPrice}
             value={priceRange[1]}
             onChange={(e) =>
-              setPriceRange([priceRange[0], parseInt(e.target.value)])
+              setPriceRange([priceRange[0], parseInt(e.target.value, 10)])
             }
             className="w-full h-2 bg-slate-300 dark:bg-gray-700 rounded-lg appearance-none cursor-pointer slider-thumb"
             aria-valuemin={minPrice}

frontend/utils/Firebase.js

@@ -23,7 +23,7 @@ if (missingFirebaseEnv.length > 0) {
 
   // React hasn't mounted yet at this point, so we write directly to the DOM
   // to avoid leaving the user with a silent blank white screen.
-  document.body.innerHTML = `
+  document.body.textContent = `
     <div style="font-family: sans-serif; max-width: 480px; margin: 80px auto; padding: 24px; text-align: center; color: #333;">
       <h2 style="color:#c0392b;">We're currently unavailable</h2>
       <p>This application is temporarily unavailable due to a configuration issue. Please try again later or contact support.</p>