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/access-guard.ts

@@ -1,6 +1,7 @@
 import { headers } from "next/headers";
 import { redirect } from "next/navigation";
 import { auth } from "@/lib/auth";
+import { isIpBlacklisted, recordRequest } from "@/lib/services/abuse-guard";
 import { prisma } from "@/lib/prisma";
 import { siteSettings } from "@/lib/services/site-settings";
 
@@ -21,14 +22,24 @@ function isExempt(path: string): boolean {
 export async function enforceSiteAccess(): Promise<void> {
   const h = await headers();
   const path = h.get("x-pathname") ?? "/";
+  const ip =
+    h.get("x-real-client-ip") ?? h.get("x-forwarded-for")?.split(",")[0]?.trim() ?? "0.0.0.0";
+
+  // Abuse/DDoS guard: count this request and block flooding IPs (no-op unless
+  // enabled in settings). Best-effort — never let it throw past the guard.
+  void recordRequest(ip).catch(() => {});
+
   if (isExempt(path)) return;
 
   let target: string | null = null;
   try {
+    // App-level IP blacklist (auto-populated by the abuse guard + /admin/ip).
+    if (await isIpBlacklisted(ip)) target = "/banned";
+
     const session = await auth();
     const rank = session?.user?.rank ?? 0;
 
-    if (await siteSettings.getBool("maintenance_enabled", false)) {
+    if (!target && (await siteSettings.getBool("maintenance_enabled", false))) {
       const minLogin = Number(await siteSettings.get("min_maintenance_login_rank", "7")) || 7;
       if (rank < minLogin) target = "/maintenance";
     }