101%: app-level DDoS guard, PWA, /api/health, API docs, worker JAR backup

Beyond parity — the web-feasible versions of the "host-only" items plus
extras AtomCMS doesn't have:
- App-level abuse/DDoS guard (src/lib/services/abuse-guard.ts): counts
  requests per IP and auto-adds flooders to website_ip_blacklist (enforced
  by the access guard) + fires ddosDetected(). OFF by default, tunable via
  settings. The iptables layer stays host-only; this is the real app-tier
  mitigation. Access guard now also enforces the IP blacklist (cached).
- PWA: a themeable web manifest (src/app/manifest.ts) + a service worker
  (public/sw.js, cache-first assets / network-first pages) registered after
  hydration — the hotel is now installable.
- /api/health: DB + emulator(RCON) + runtime status probe.
- /developers: a public API documentation page covering every REST endpoint
  with its method, path and auth requirement.
- jobs-worker: daily emulator JAR backup (runs host-side in the worker, like
  AtomCMS's backup command) — copies + prunes; no-ops unless EMULATOR_JAR_PATH
  + EMULATOR_BACKUP_DIR are set.

Verified live (prod, amx_test): /api/health ok, manifest + sw served, docs
page renders, normal pages unaffected by the guard. tsc 0, vitest 49/49,
next build 0.

src/lib/services/abuse-guard.ts

@@ -0,0 +1,85 @@
+import { ddosDetected } from "@/lib/services/alert";
+import { prisma } from "@/lib/prisma";
+import { siteSettings } from "@/lib/services/site-settings";
+
+/**
+ * App-level abuse / DDoS guard — the web-tier-feasible half of AtomCMS's DDoS
+ * protection. It can't touch iptables (that's a host-only optimisation), but it
+ * DOES the actual mitigation a CMS needs: count requests per IP and, when one
+ * floods past the threshold, add it to website_ip_blacklist (which the access
+ * guard then enforces) and fire the existing ddosDetected() alert.
+ *
+ * OFF by default; staff enable + tune it via website_settings:
+ *   abuse_guard_enabled ("1"), abuse_guard_threshold (req, default 200),
+ *   abuse_guard_window_seconds (default 10).
+ */
+type Bucket = { count: number; resetAt: number };
+const buckets = new Map<string, Bucket>();
+const recentlyBlocked = new Set<string>();
+
+let blacklist = new Set<string>();
+let blacklistLoadedAt = 0;
+const BLACKLIST_TTL = 30_000;
+
+function isPrivate(ip: string): boolean {
+  return (
+    !ip ||
+    ip === "0.0.0.0" ||
+    ip === "::1" ||
+    ip.startsWith("127.") ||
+    ip.startsWith("10.") ||
+    ip.startsWith("192.168.")
+  );
+}
+
+/** Cached blacklist lookup (refreshed every 30s — no DB hit per request). */
+export async function isIpBlacklisted(ip: string): Promise<boolean> {
+  if (isPrivate(ip)) return false;
+  const now = Date.now();
+  if (now - blacklistLoadedAt >= BLACKLIST_TTL) {
+    try {
+      const rows = await prisma.websiteIpBlacklist.findMany({ select: { ipAddress: true } });
+      blacklist = new Set(rows.map((r) => r.ipAddress));
+      blacklistLoadedAt = now;
+    } catch {
+      /* keep stale set on DB error */
+    }
+  }
+  return blacklist.has(ip);
+}
+
+/** Count a request; auto-blacklist + alert the IP if it floods (when enabled). */
+export async function recordRequest(ip: string): Promise<void> {
+  if (isPrivate(ip)) return;
+  if (!(await siteSettings.getBool("abuse_guard_enabled", false))) return;
+
+  const limit = Number(await siteSettings.get("abuse_guard_threshold", "200")) || 200;
+  const windowMs =
+    (Number(await siteSettings.get("abuse_guard_window_seconds", "10")) || 10) * 1000;
+
+  const now = Date.now();
+  if (buckets.size > 10_000) {
+    for (const [k, v] of buckets) if (now >= v.resetAt) buckets.delete(k);
+  }
+
+  const b = buckets.get(ip);
+  if (!b || now >= b.resetAt) {
+    buckets.set(ip, { count: 1, resetAt: now + windowMs });
+    return;
+  }
+  b.count += 1;
+
+  if (b.count >= limit && !recentlyBlocked.has(ip)) {
+    recentlyBlocked.add(ip);
+    setTimeout(() => recentlyBlocked.delete(ip), 60_000);
+    try {
+      await prisma.websiteIpBlacklist.create({
+        data: { ipAddress: ip, createdAt: new Date(), updatedAt: new Date() },
+      });
+      blacklistLoadedAt = 0; // force a refresh so the block takes effect at once
+      await ddosDetected(ip, b.count);
+    } catch {
+      /* ignore — alert/blacklist best-effort */
+    }
+  }
+}