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/EventsBridge.tsx

@@ -0,0 +1,51 @@
+"use client";
+
+import { useQueryClient } from "@tanstack/react-query";
+import { useSession } from "next-auth/react";
+import { useEffect } from "react";
+
+export function EventsBridge() {
+  const { data: session, status } = useSession();
+  const queryClient = useQueryClient();
+
+  useEffect(() => {
+    if (status !== "authenticated" || !session) return;
+    if (typeof window === "undefined" || !("EventSource" in window)) return;
+
+    let closed = false;
+    let es: EventSource | null = null;
+
+    const connect = () => {
+      if (closed) return;
+      es = new EventSource("/api/events");
+
+      es.addEventListener("status", (e: MessageEvent) => {
+        try {
+          queryClient.setQueryData(["status"], JSON.parse(e.data));
+        } catch {}
+      });
+      es.addEventListener("chat", (e: MessageEvent) => {
+        try {
+          queryClient.setQueryData(["chat"], JSON.parse(e.data));
+        } catch {}
+      });
+
+      es.onerror = () => {
+        // Browser auto-retries, but if the server closed after the 10m cap
+        // we want a clean reconnect rather than tight reconnect loops.
+        if (closed) return;
+        es?.close();
+        es = null;
+        setTimeout(connect, 3000);
+      };
+    };
+
+    connect();
+    return () => {
+      closed = true;
+      es?.close();
+    };
+  }, [status, session, queryClient]);
+
+  return null;
+}