Track week-over-week movement in the Intelligence Index

- sync-catalog keeps a rolling 52-week history of index scores
- the matrix shows the delta since the previous refresh plus a biggest-mover card

scripts/sync-catalog.mjs

@@ -272,6 +272,27 @@ export const RAW = ${JSON.stringify(scores, null, 1)};
 
 writeFileSync(resolve(ROOT, "site/assets/snapshot.json"), JSON.stringify(snapshot, null, 2) + "\n");
 
+/* --- rolling history (one entry per refresh, last 52 weeks) ---------------- */
+let history = [];
+try {
+  history = JSON.parse(await (await import("node:fs/promises")).readFile(resolve(ROOT, "site/assets/history.json"), "utf8"));
+} catch {
+  /* first run */
+}
+const week = snapshot.generated.slice(0, 10);
+if (!history.length || history[0].date !== week) {
+  history.unshift({
+    date: week,
+    scores: Object.fromEntries(scores.filter((s) => s.ii !== null).map((s) => [s.id, s.ii]))
+  });
+  history = history.slice(0, 52);
+}
+writeFileSync(resolve(ROOT, "site/assets/history.json"), JSON.stringify(history, null, 1) + "\n");
+writeFileSync(
+  resolve(ROOT, "site/assets/history.js"),
+  `// AUTO-GENERATED by scripts/sync-catalog.mjs — do not edit by hand.\n// Rolling week-over-week snapshot of the Intelligence Index.\nexport const HISTORY = ${JSON.stringify(history, null, 1)};\n`
+);
+
 console.log("\nnew models:", newModels.length ? newModels.join(", ") : "none");
 console.log("removed models:", removedModels.length ? removedModels.join(", ") : "none");
 if (deltas.length) {
@@ -280,4 +301,4 @@ if (deltas.length) {
 } else {
   console.log("score changes: none");
 }
-console.log("\nwrote site/assets/catalog.js, evals.js, snapshot.json");
+console.log("\nwrote site/assets/catalog.js, evals.js, snapshot.json, history.json");