feat(auth): user-management audit log (table + record sites + /api/audit endpoint)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/web/api/audit.ts

@@ -0,0 +1,18 @@
+import { Router } from "express";
+import type { AuditStore } from "../../data/audit.js";
+
+export function createAuditRouter(audit: AuditStore): Router {
+  const router = Router();
+  router.get("/", (req, res) => {
+    const limit = clampInt(req.query.limit, 1, 500, 100);
+    const offset = clampInt(req.query.offset, 0, 100_000, 0);
+    res.json({ entries: audit.list(limit, offset) });
+  });
+  return router;
+}
+
+function clampInt(v: unknown, min: number, max: number, def: number): number {
+  const n = typeof v === "string" ? parseInt(v, 10) : NaN;
+  if (!Number.isFinite(n)) return def;
+  return Math.min(Math.max(n, min), max);
+}