feat(seo): add keywords meta tag support for improved SEO

- Introduced keywords property in layout and page server files to enhance SEO capabilities.
- Updated relevant components to include keywords in meta tags for better search engine visibility.

src/routes/+layout.svelte

@@ -20,6 +20,7 @@
     seoDescription?: string;
     socialImage?: string;
     robots?: string;
+    keywords?: string;
     jsonLd?: Record<string, unknown> | Record<string, unknown>[];
     breadcrumbItems?: { href?: string; label: string }[];
     topBanner?: {
@@ -185,6 +186,9 @@
   {#if seoDescription}
     <meta name="description" content={seoDescription} />
   {/if}
+  {#if pageData?.keywords}
+    <meta name="keywords" content={pageData.keywords} />
+  {/if}
   <link rel="canonical" href={canonical} />
   <!-- Open Graph -->
   <meta property="og:type" content="website" />