Heartbeat and nicer status line

public/assets/app.js

@@ -388,7 +388,7 @@ async function refreshStatus() {
     const response = await fetch('/api/status', { cache: 'no-store' });
     const status = await response.json();
     if (!response.ok) throw new Error('status failed');
-    setStat('status', status.ok ? 'ONLINE' : 'DEGRADED');
+    setStat('status', `${status.ok ? 'ONLINE' : 'DEGRADED'} ${formatUptime(status.uptimeSeconds)}`);
     setStat('latency', `${Math.max(1, Math.round(performance.now() - started))}MS`);
     setStat('nodes', formatCount(status.liveClients));
     setStat('memes', formatCount(status.memeCount));
@@ -406,6 +406,21 @@ function setStat(name, value) {
   }
 }
 
+function formatUptime(value) {
+  const seconds = Math.max(0, Number.isFinite(value) ? value : 0);
+  const minutes = Math.floor(seconds / 60);
+  if (minutes < 1) return `UP ${seconds}S`;
+  if (minutes < 60) return `UP ${minutes}M`;
+
+  const hours = Math.floor(minutes / 60);
+  const remainingMinutes = minutes % 60;
+  if (hours < 24) return `UP ${hours}H${remainingMinutes > 0 ? ` ${remainingMinutes}M` : ''}`;
+
+  const days = Math.floor(hours / 24);
+  const remainingHours = hours % 24;
+  return `UP ${days}D${remainingHours > 0 ? ` ${remainingHours}H` : ''}`;
+}
+
 function updateScrollIndicator() {
   const segments = [...scrollIndicator.querySelectorAll('span')];
   const maxScroll = Math.max(1, document.documentElement.scrollHeight - window.innerHeight);

server.js

@@ -18,6 +18,7 @@ const DATA_DIR = process.env.DATA_DIR || './data';
 const PAGE_SIZE_MAX = 48;
 const UPLOAD_MAX_BYTES = 5 * 1024 * 1024;
 const REQUEST_MAX_BYTES = 6 * 1024 * 1024;
+const SSE_HEARTBEAT_MS = 25_000;
 const events = new Set();
 const DISCOVERY_ROUTES = new Set([
   '/robots.txt',
@@ -135,11 +136,19 @@ const server = http.createServer(async (req, res) => {
       res.writeHead(200, {
         'Content-Type': 'text/event-stream; charset=utf-8',
         'Cache-Control': 'no-cache, no-transform',
-        Connection: 'keep-alive'
+        Connection: 'keep-alive',
+        'X-Accel-Buffering': 'no'
       });
+      res.write('retry: 5000\n');
       res.write('event: ready\ndata: {}\n\n');
       events.add(res);
-      req.on('close', () => events.delete(res));
+      const heartbeat = setInterval(() => {
+        res.write(': keep-alive\n\n');
+      }, SSE_HEARTBEAT_MS);
+      req.on('close', () => {
+        clearInterval(heartbeat);
+        events.delete(res);
+      });
       return;
     }