site: upgrade Astro 5 → 7

- astro 7.0.7, @astrojs/mdx 7, sitemap 3.7, rss 4.0.19, check 0.9.9
- trailingSlash 'always' → 'ignore': Astro 7 generates prerender paths for
  dynamic extension endpoints (/categories/<c>/rss.xml) with a trailing
  slash under 'always' but builds their route patterns without one, so the
  build fails with "Missing parameter"; directory-format output is
  identical either way. Also removes the now-unneeded dev feed-slash shim.
- compressHTML: true pinned to keep pre-v7 whitespace behavior
- zod 4: import z from 'astro/zod' (astro:content re-export deprecated),
  z.string().url() → z.url()
- npm audit fix (fast-uri, fast-xml-builder, yaml)

Claude-Session: https://claude.ai/code/session_01WZaczDJjL3xZ3u5spsN5AL

astro.config.mjs

@@ -128,26 +128,20 @@ const setPickApi = {
   },
 };
 
-// With trailingSlash 'always', the dev server only matches dynamic-route
-// endpoints (/tags/<t>/rss.xml, /categories/<c>/rss.xml) when the request
-// has a trailing slash; the built site serves them as plain files without
-// one. Rewrite in dev so the same URLs work in both.
-const feedSlashShim = {
-  name: 'feed-trailing-slash-dev-shim',
-  apply: 'serve',
-  configureServer(server) {
-    server.middlewares.use((req, _res, next) => {
-      if (/^\/(tags|categories|topics)\/[^/]+\/rss\.xml$/.test(req.url)) req.url += '/';
-      next();
-    });
-  },
-};
-
 export default defineConfig({
   site: 'https://unique.rzen.dev',
-  trailingSlash: 'always',
+  // 'ignore', not 'always': Astro 7 generates prerender paths for dynamic
+  // extension endpoints (/categories/<c>/rss.xml) with a trailing slash under
+  // 'always' but builds their route patterns without one, so the build dies
+  // with "Missing parameter". Directory-format output is identical either
+  // way, and 'ignore' also lets the dev server match those endpoints without
+  // the old feed-trailing-slash shim.
+  trailingSlash: 'ignore',
+  // Keep the pre-v7 whitespace behavior; the v7 default 'jsx' collapses
+  // whitespace between adjacent inline elements.
+  compressHTML: true,
   build: { format: 'directory' },
-  vite: { plugins: [editFindTagApi, setPickApi, feedSlashShim] },
+  vite: { plugins: [editFindTagApi, setPickApi] },
   integrations: [
     mdx(),
     sitemap({