site: ui/ux refresh, seo pass, find/lists indexes, 25 new finds

- newspaper-style masthead (stats | "Unique" | About/Blog) on every page
  with per-page italic subheader + last-updated date on listing pages;
  sitewide 42rem reading width
- pinterest home (hero + masonry, "load more"); old list view at /index3/
- new pages: /about, /blog, /legal, /find/, /finds/, custom 404
- footer collection links now clickable; "founded" stat replaces "updated"
  in the masthead
- centralised SEO component with per-page json-ld (Review, BlogPosting,
  Product, Article, CollectionPage, ItemList, BreadcrumbList, etc.);
  @astrojs/sitemap + @astrojs/rss; robots.txt; promoted finds canonical
  to their review
- memoize getSiteStats() so the masthead/footer counts don't multiply
  per-page build cost
- 25 new daily-finds captures

astro.config.mjs

@@ -1,7 +1,22 @@
 import { defineConfig } from 'astro/config';
 import mdx from '@astrojs/mdx';
+import sitemap from '@astrojs/sitemap';
+
+const EXCLUDED_PATHS = new Set([
+  'https://unique.rzen.dev/grid/',
+  'https://unique.rzen.dev/index3/',
+  'https://unique.rzen.dev/404/',
+]);
 
 export default defineConfig({
   site: 'https://unique.rzen.dev',
-  integrations: [mdx()],
+  trailingSlash: 'always',
+  build: { format: 'directory' },
+  integrations: [
+    mdx(),
+    sitemap({
+      filter: (page) => !EXCLUDED_PATHS.has(page),
+      changefreq: 'weekly',
+    }),
+  ],
 });