SSE events bridge, PWA service worker, offline banner, lazy admin tabs

- New /api/events SSE endpoint (authed): pushes status every 5s and chat
  on log-file mtime change (~1.5s poll). Heartbeat every 15s, hard-caps
  each stream at 10min so the browser gets a clean auth refresh on
  reconnect. Auto-aborts on client disconnect.
- Factored shared helpers out of the existing routes:
  - lib/server-status.ts (probeStatus, reused by /api/status + SSE)
  - lib/chat-log.ts (parseLogLine, readChatMessages, logMtime, reused by
    /api/chat + SSE)
- EventsBridge client (mounted in Providers) opens one EventSource per
  authed session and writes live data into the TanStack Query cache for
  ["status"] and ["chat"] — no refactor needed in consuming components,
  they keep reading their usual query keys.
- Now that SSE pushes updates, polling intervals bumped: StatusCard and
  ServerControls 10s -> 60s, ChatBridge 5s -> 30s. SSE handles realtime,
  polling is safety fallback.
- OfflineBanner: sticky amber bar when navigator.onLine flips false.
- PWA: minimal public/sw.js with shell + asset cache (network-first for
  HTML, stale-while-revalidate for static assets, never touches /api/*
  or text/event-stream). ServiceWorkerRegister client registers it in
  production only.
- AdminTabs now uses next/dynamic with skeleton fallbacks for Players /
  Chat / Mods / Backups / Logs, keeping initial /admin bundle smaller.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

components/ServiceWorkerRegister.tsx

@@ -0,0 +1,22 @@
+"use client";
+
+import { useEffect } from "react";
+
+export function ServiceWorkerRegister() {
+  useEffect(() => {
+    if (typeof navigator === "undefined") return;
+    if (!("serviceWorker" in navigator)) return;
+    if (process.env.NODE_ENV !== "production") return;
+
+    const register = () => {
+      navigator.serviceWorker
+        .register("/sw.js", { scope: "/" })
+        .catch(() => {});
+    };
+
+    if (document.readyState === "complete") register();
+    else window.addEventListener("load", register, { once: true });
+  }, []);
+
+  return null;
+}