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/app/layout.tsx

@@ -4,6 +4,7 @@ import { getLocale, getMessages } from "next-intl/server";
 import { Nunito } from "next/font/google";
 import type { ReactNode } from "react";
 import { Navigation } from "@/components/navigation";
+import { PwaRegister } from "@/components/pwa-register";
 import RadioPlayerGate from "@/components/public/radio-player-gate";
 import { SiteFooter } from "@/components/site-footer";
 import { SiteHeader } from "@/components/site-header";
@@ -61,6 +62,7 @@ export default async function RootLayout({ children }: { children: ReactNode })
           </main>
           <SiteFooter />
           <RadioPlayerGate />
+          <PwaRegister />
         </NextIntlClientProvider>
       </body>
     </html>