ads: pin aja-colorbox-300x250 as the first banner in every 300x250 rotation

src/lib/ads.ts

@@ -196,10 +196,38 @@ export function shuffle<T>(arr: T[]): T[] {
   return out;
 }
 
+// Slugs (or campaign_ids) that must be the FIRST banner of their size in
+// every rotation, ahead of the shuffled pool. AJA 2026 sits at the top of
+// every 300x250 stack per Ryan 2026-06-16.
+const PINNED_SLUGS_BY_SIZE: Partial<Record<Ad["size"], string[]>> = {
+  "300x250": ["aja-colorbox-300x250"],
+};
+
 export function rotateAll(size: Ad["size"], exclude: Set<string> = new Set()): Ad[] {
   const pool = readCachedAds().filter((a) => a.size === size);
   const key = (a: Ad) => a.src ?? a.label;
-  return shuffle(pool.filter((a) => !exclude.has(key(a))));
+  const remaining = pool.filter((a) => !exclude.has(key(a)));
+
+  const pinnedSlugs = PINNED_SLUGS_BY_SIZE[size] || [];
+  if (pinnedSlugs.length === 0) return shuffle(remaining);
+
+  const pinned: Ad[] = [];
+  const rest: Ad[] = [];
+  for (const ad of remaining) {
+    const slugMatch = ad.slug && pinnedSlugs.includes(ad.slug);
+    const idMatch = ad.campaign_id && pinnedSlugs.includes(ad.campaign_id);
+    if (slugMatch || idMatch) {
+      pinned.push(ad);
+    } else {
+      rest.push(ad);
+    }
+  }
+  pinned.sort((a, b) => {
+    const ai = pinnedSlugs.indexOf((a.slug || a.campaign_id) ?? "");
+    const bi = pinnedSlugs.indexOf((b.slug || b.campaign_id) ?? "");
+    return ai - bi;
+  });
+  return [...pinned, ...shuffle(rest)];
 }
 
 export function pickAds(