feat: print-friendly layout + comment count on every post overview

- Hides Header / HeaderOverlay / Footer / TopBanner / Breadcrumbs and
  the comment accordion when printing. Action toolbar already had
  `print:hidden`.
- Adds @media print rules in app.css: 1.5cm page margins, 11pt body,
  forced black-on-white, expand link URLs after anchor text inside
  articles, keep images and headings together at page breaks.
- PostCard now renders the count pill whenever a value is known (incl.
  zero); previously hidden for `count === 0`, so posts whose comments
  are still pending always looked empty.
- Extracts the bulk-fetch helper to `lib/comment-counts.ts`
  (`fetchCommentCounts` + `postSlugForComments`) and uses it from both
  `BlogOverview` and `PostOverviewBlock`. Homepage / any page with a
  post_overview block now shows the badges too — previously only the
  paginated /posts/* routes did.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/lib/components/BlogOverview.svelte

@@ -8,7 +8,7 @@
   import { postHref } from "$lib/blog-utils";
   import { t as tStatic, T } from "$lib/translations";
   import type { Translations } from "$lib/translations";
-  import { env } from "$env/dynamic/public";
+  import { fetchCommentCounts, postSlugForComments, type CommentCountsMap } from "$lib/comment-counts";
 
   interface TagEntry {
     _slug?: string;
@@ -115,43 +115,15 @@
 
   const totalCount = $derived(totalPosts);
 
-  // Bulk-fetch comment counts for the visible posts. Uses a single
-  // `/api/comments/counts` request keyed on the post slug. Failures keep the
-  // map empty so cards just don't render the badge.
-  let commentCounts = $state<Record<string, number>>({});
-
-  function postSlug(p: PostEntry): string {
-    const raw = (p as { slug?: string; _slug?: string }).slug ?? p._slug ?? "";
-    return raw.replace(/^\//, "").trim();
-  }
-
+  // Bulk-fetch comment counts for the visible posts (single request per render).
+  let commentCounts = $state<CommentCountsMap>({});
   $effect(() => {
-    const slugs = posts.map(postSlug).filter(Boolean);
-    if (slugs.length === 0) {
-      commentCounts = {};
-      return;
-    }
-    const cmsBase = (
-      env.PUBLIC_CMS_URL ||
-      import.meta.env.PUBLIC_CMS_URL ||
-      ""
-    ).replace(/\/$/, "");
-    if (!cmsBase) return;
-    const url = new URL(`${cmsBase}/api/comments/counts`);
-    url.searchParams.set("ids", slugs.join(","));
-    let cancelled = false;
-    fetch(url.toString())
-      .then((r) => (r.ok ? r.json() : { counts: {} }))
-      .then((d) => {
-        if (cancelled) return;
-        commentCounts = (d?.counts ?? {}) as Record<string, number>;
-      })
-      .catch(() => {
-        if (!cancelled) commentCounts = {};
+    const ctrl = new AbortController();
+    fetchCommentCounts(posts.map(postSlugForComments), { signal: ctrl.signal })
+      .then((map) => {
+        commentCounts = map;
       });
-    return () => {
-      cancelled = true;
-    };
+    return () => ctrl.abort();
   });
 </script>
 
@@ -298,7 +270,7 @@
           post={post}
           href={postHref(post)}
           tagBase={`${basePath}/tag`}
-          commentCount={commentCounts[postSlug(post)] ?? null}
+          commentCount={commentCounts[postSlugForComments(post)] ?? null}
         />
       {/each}
     </div>