astro check restored: tsconfig excludes public/ (the 2 MB vendored CMS bundle was what exhausted the heap) and extends tsconfigs/strict; type annotations in template scripts, z from astro/zod; exact version pins; compressHTML true (lossless whitespace, no words glued to links) and explicit trailingSlash/build.format; README: upgrading section

src/pages/news/[...page].astro

@@ -16,7 +16,7 @@ export async function getStaticPaths() {
   const chunks = [posts.slice(0, FIRST)];
   for (let i = FIRST; i < posts.length; i += REST) chunks.push(posts.slice(i, i + REST));
   const lastPage = chunks.length;
-  const hrefOf = (n) => (n === 1 ? '/news' : `/news/${n}`);
+  const hrefOf = (n: number) => (n === 1 ? '/news' : `/news/${n}`);
   return chunks.map((data, i) => {
     const n = i + 1;
     return {
@@ -42,7 +42,7 @@ for (let n = 1; n <= page.lastPage; n++) {
   if (n === 1 || n === page.lastPage || Math.abs(n - page.currentPage) <= 1) nums.push(n);
   else if (nums.at(-1) !== 0) nums.push(0);
 }
-const hrefFor = (n) => (n === 1 ? '/news' : `/news/${n}`);
+const hrefFor = (n: number) => (n === 1 ? '/news' : `/news/${n}`);
 ---
 <Base
   title={first ? 'CTAO Science Portal - News' : `CTAO Science Portal - News, page ${page.currentPage}`}

src/pages/news/[slug].astro

@@ -96,10 +96,10 @@ const readMin = readMinOf(post);
   // enters it is mapped back to its governing h2/h3, whose TOC link(s) get
   // aria-current="true" (set in BOTH renderings — inline <details> and rail).
   // Progressive enhancement: without JS the TOC is plain working anchors.
-  const links = [...document.querySelectorAll('.toc a[href^="#"]')];
+  const links = [...document.querySelectorAll<HTMLAnchorElement>('.toc a[href^="#"]')];
   if (links.length) {
-    let current = [];
-    const setCurrent = (id) => {
+    let current: HTMLAnchorElement[] = [];
+    const setCurrent = (id: string | null) => {
       const next = id ? links.filter((a) => decodeURIComponent(a.hash.slice(1)) === id) : [];
       if (next[0] === current[0]) return;
       for (const a of current) a.removeAttribute('aria-current');
@@ -108,35 +108,36 @@ const readMin = readMinOf(post);
     };
     const blocks = [...document.querySelectorAll('.prose > *')];
     // Governing heading = the block itself or the nearest h2/h3[id] above it
-    const headingFor = (el) => {
+    const headingFor = (el: Element) => {
       for (let i = blocks.indexOf(el); i >= 0; i--) {
         if (blocks[i].matches('h2[id], h3[id]')) return blocks[i].id;
       }
       return null; // intro before the first heading — nothing highlighted
     };
-    const onIntersect = (entries) => {
+    const onIntersect = (entries: IntersectionObserverEntry[]) => {
       for (const e of entries) {
         if (e.isIntersecting) { setCurrent(headingFor(e.target)); break; }
       }
     };
-    let observer;
+    let observer: IntersectionObserver | undefined;
     const observe = () => {
       observer?.disconnect();
       // Narrow band below the sticky header (--header-h 56px + 12px slack;
       // JS can't read the token cheaply, keep in sync) — Starlight's rootMargin trick
       const top = 68, band = 64;
-      observer = new IntersectionObserver(onIntersect, {
+      const io = new IntersectionObserver(onIntersect, {
         rootMargin: `-${top}px 0px ${top + band - document.documentElement.clientHeight}px`,
       });
-      blocks.forEach((b) => observer.observe(b));
+      observer = io;
+      blocks.forEach((b) => io.observe(b));
     };
     observe();
-    let timer;
+    let timer: ReturnType<typeof setTimeout> | undefined;
     addEventListener('resize', () => { clearTimeout(timer); timer = setTimeout(observe, 200); });
     // Short final section: at page bottom, the last heading wins
     addEventListener('scroll', () => {
       if (innerHeight + scrollY >= document.documentElement.scrollHeight - 4) {
-        setCurrent(headingFor(blocks.at(-1)));
+        setCurrent(headingFor(blocks[blocks.length - 1]));
       }
     }, { passive: true });
   }