feat: add product catalog with filters, product detail page with AR support, enhanced homepage

- Backend: add GET /api/products/search (full-text) and GET /api/products/featured endpoints; update GET /:id to include related_products (same category, limit 4)
- Products.tsx: full rewrite with sidebar filters (METI toggle prominent first, category buttons, price bands), sort dropdown, 12-per-page pagination, search bar calling /search endpoint, empty state, responsive 1/2/3 col grid
- ProductDetail.tsx: new page with image, name/name_ja, price, METI badge, craftsman link, description, AR button (amber, only when ar_model_url + ar_eligible=true), ar_ineligible_reason badge, add-to-cart (login-gated), related products grid (max 4), reviews section (max 5, star rating)
- App.tsx: add /products/:id route for ProductDetail
- Home.tsx: category tiles already link to /products?category=<key>; add New Arrivals section fetching /api/products/featured showing 4-col product card grid

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/routes/products.js

@@ -45,7 +45,50 @@ router.get('/', async (req, res) => {
   }
 });
 
-// Get product by ID
+// Full-text search
+router.get('/search', async (req, res) => {
+  try {
+    const pool = getPool();
+    const { q } = req.query;
+    if (!q || q.trim() === '') {
+      return res.json([]);
+    }
+    const searchTerm = `%${q.trim()}%`;
+    const { rows } = await pool.query(
+      `SELECT p.*, c.shop_name, c.meti_certified as craftsman_meti, c.prefecture
+       FROM products p JOIN craftsmen c ON p.craftsman_id = c.id
+       WHERE p.is_active = true
+         AND (p.name ILIKE $1 OR COALESCE(p.name_ja,'') ILIKE $1 OR COALESCE(p.description,'') ILIKE $1)
+       ORDER BY p.is_featured DESC, p.created_at DESC
+       LIMIT 20`,
+      [searchTerm]
+    );
+    res.json(rows);
+  } catch (err) {
+    console.error(err);
+    res.status(500).json({ error: 'Failed to search products' });
+  }
+});
+
+// Featured products
+router.get('/featured', async (req, res) => {
+  try {
+    const pool = getPool();
+    const { rows } = await pool.query(
+      `SELECT p.*, c.shop_name, c.meti_certified as craftsman_meti, c.prefecture
+       FROM products p JOIN craftsmen c ON p.craftsman_id = c.id
+       WHERE p.is_active = true
+       ORDER BY p.is_featured DESC, p.created_at DESC
+       LIMIT 8`
+    );
+    res.json(rows);
+  } catch (err) {
+    console.error(err);
+    res.status(500).json({ error: 'Failed to fetch featured products' });
+  }
+});
+
+// Get product by ID (with related products)
 router.get('/:id', async (req, res) => {
   try {
     const pool = getPool();
@@ -58,6 +101,8 @@ router.get('/:id', async (req, res) => {
     
     if (rows.length === 0) return res.status(404).json({ error: 'Product not found' });
     
+    const product = rows[0];
+
     // Get reviews
     const reviews = await pool.query(
       `SELECT r.*, u.display_name FROM reviews r
@@ -65,9 +110,22 @@ router.get('/:id', async (req, res) => {
        WHERE r.product_id = $1 ORDER BY r.created_at DESC LIMIT 10`,
       [req.params.id]
     );
+
+    // Get related products (same craft_category, different product, limit 4)
+    const related = await pool.query(
+      `SELECT p.*, c.shop_name, c.meti_certified as craftsman_meti, c.prefecture
+       FROM products p JOIN craftsmen c ON p.craftsman_id = c.id
+       WHERE p.is_active = true
+         AND p.craft_category = $1
+         AND p.id != $2
+       ORDER BY p.is_featured DESC, p.created_at DESC
+       LIMIT 4`,
+      [product.craft_category, req.params.id]
+    );
     
-    res.json({ ...rows[0], reviews: reviews.rows });
+    res.json({ ...product, reviews: reviews.rows, related_products: related.rows });
   } catch (err) {
+    console.error(err);
     res.status(500).json({ error: 'Failed to fetch product' });
   }
 });