feat(w3c): auto-refresh groups list every 24 hours

Adds a setInterval that calls the update script daily and reloads
the in-memory groups data from disk. Follows the existing pattern
from xref's periodic cache invalidation.

Also handles missing groups.json gracefully at startup (empty store
instead of crash).

Closes #395

Author: marcoscaceres

routes/w3c/group.ts

@@ -1,10 +1,11 @@
 import path from "path";
-import { readFileSync } from "fs";
+import { readFileSync, existsSync } from "fs";
 
 import { Request, Response } from "express";
 
 import { MemCache } from "../../utils/mem-cache.js";
 import { env, ms, seconds, HTTPError } from "../../utils/misc.js";
+import update from "../../scripts/update-w3c-groups-list.js";
 
 const DATA_DIR = env("DATA_DIR");
 const dataSource = path.join(DATA_DIR, "w3c/groups.json");
@@ -18,7 +19,33 @@ type GroupType = "wg" | "cg" | "ig" | "bg" | "other";
 export type Groups = Record<string, GroupMeta>;
 export type GroupsByType = Record<GroupType, Groups>;
 
-const groups: GroupsByType = JSON.parse(readFileSync(dataSource, "utf-8"));
+let groups: GroupsByType = existsSync(dataSource)
+  ? JSON.parse(readFileSync(dataSource, "utf-8"))
+  : { wg: {}, cg: {}, ig: {}, bg: {}, other: {} };
+
+function reloadGroups() {
+  try {
+    if (existsSync(dataSource)) {
+      groups = JSON.parse(readFileSync(dataSource, "utf-8"));
+      cache.clear();
+    }
+  } catch (error) {
+    console.error("Failed to reload groups.json:", error);
+  }
+}
+
+async function refreshGroups() {
+  try {
+    await update();
+    reloadGroups();
+    console.log("W3C groups list refreshed.");
+  } catch (error) {
+    console.error("Failed to refresh W3C groups:", error);
+  }
+}
+
+setInterval(refreshGroups, ms("24h"));
+if (!existsSync(dataSource)) refreshGroups();
 
 interface Group {
   id: number;