SEO overhaul: product schema, dynamic sitemap, favicon, og-image fix

- product.php: set metaTitle, metaDescription, canonicalUrl, ogImage,
  ogType=product, productSchema (JSON-LD with price/availability/reviews),
  and breadcrumbs variables for header.php to consume
- sitemap.php: dynamic XML sitemap generated from DB — includes all 30
  active products + static pages; robots.txt now points here
- header.php: fix favicon links (favicon.ico in root + icon-192.png);
  fix productSchema output (was double-encoding via json_encode)
- robots.txt: point Sitemap directive to /sitemap.php

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

product.php

@@ -23,9 +23,6 @@ if (!$product) {
     exit;
 }
 
-$pageTitle = $product['name'] . " - Tom's Java Jive";
-$pageDescription = truncate(strip_tags($product['description']), 160);
-
 // Get product reviews
 $reviews = db()->fetchAll(
     "SELECT * FROM reviews WHERE product_id = :id AND is_approved = 1 ORDER BY created_at DESC LIMIT 10",
@@ -49,6 +46,53 @@ $mainImage = !empty($images) ? $images[0] : '/assets/images/placeholder-product.
 $salePrice = $product['sale_price'];
 $price = $product['price'];
 $inStock = $product['stock'] > 0;
+$displayPrice = $salePrice ?? $price;
+
+// SEO meta
+$categoryLabel = ucfirst($product['category'] ?? 'Coffee');
+$metaTitle = $product['name'] . ' ' . $categoryLabel . " Coffee | Tom's Java Jive";
+$metaDescription = truncate(strip_tags($product['description'] ?? ''), 155)
+    ?: $product['name'] . ' flavored artisan coffee beans freshly roasted in Weatherford, TX. Available in whole bean and ground. Ships nationwide.';
+$metaKeywords = strtolower($product['name']) . ' coffee, ' . strtolower($categoryLabel) . ' coffee, flavored coffee beans, artisan coffee, buy coffee online';
+$canonicalUrl = 'https://tomsjavajive.com/product.php?id=' . $productId;
+$ogType = 'product';
+$ogImage = (strpos($mainImage, 'http') === 0) ? $mainImage : 'https://tomsjavajive.com' . $mainImage;
+
+// Structured data — Product schema
+$productSchemaData = [
+    '@context' => 'https://schema.org',
+    '@type'    => 'Product',
+    'name'     => $product['name'] . ' ' . $categoryLabel . ' Coffee',
+    'url'      => $canonicalUrl,
+    'image'    => $ogImage,
+    'description' => $metaDescription,
+    'brand'    => ['@type' => 'Brand', 'name' => "Tom's Java Jive"],
+    'offers'   => [
+        '@type'         => 'Offer',
+        'priceCurrency' => 'USD',
+        'price'         => number_format((float) $displayPrice, 2, '.', ''),
+        'availability'  => $inStock ? 'https://schema.org/InStock' : 'https://schema.org/OutOfStock',
+        'url'           => $canonicalUrl,
+        'seller'        => ['@type' => 'Organization', 'name' => "Tom's Java Jive"],
+    ],
+];
+if ($reviewCount > 0) {
+    $productSchemaData['aggregateRating'] = [
+        '@type'       => 'AggregateRating',
+        'ratingValue' => round($avgRating, 1),
+        'reviewCount' => $reviewCount,
+        'bestRating'  => 5,
+        'worstRating' => 1,
+    ];
+}
+$productSchema = json_encode($productSchemaData, JSON_UNESCAPED_SLASHES);
+
+// Breadcrumbs
+$breadcrumbs = [
+    ['name' => 'Home', 'url' => 'https://tomsjavajive.com/'],
+    ['name' => 'Shop', 'url' => 'https://tomsjavajive.com/shop.php'],
+    ['name' => $product['name'], 'url' => $canonicalUrl],
+];
 
 require_once __DIR__ . '/includes/header.php';
 ?>