feat: link health summary, recently resolved panel, event duration

- dashboard: pass recent_resolved (last 24h, limit 10) to index template;
  render "Recently Resolved" section showing type, target, resolved time,
  and calculated duration (first_seen → resolved_at)
- dashboard: event-age spans now also update via setInterval; duration
  shown for resolved events (e.g. "2h 15m")
- links page: link health summary panel shows server iface count,
  error/flap counts, switch port up/down, PoE total draw/capacity bar;
  only shows problematic stats if non-zero; shows "All OK ✔" when clean
- style.css: new classes for summary panel, resolved row/badge

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

templates/links.html

@@ -462,6 +462,74 @@ function expandAll() {
   });
 }
 
+// ── Link health summary ───────────────────────────────────────────
+function buildLinkSummary(hosts, unifiSwitches) {
+  let svrTotal = 0, svrErrors = 0, svrFlap = 0;
+  let swTotal = 0, swUp = 0, swDown = 0, swErrors = 0;
+  let poeDrawW = 0, poeMaxW = 0;
+
+  for (const ifaces of Object.values(hosts)) {
+    for (const d of Object.values(ifaces)) {
+      svrTotal++;
+      if ((d.tx_errs_rate || 0) > 0.01 || (d.rx_errs_rate || 0) > 0.01) svrErrors++;
+      if ((d.carrier_changes || 0) > 10) svrFlap++;
+    }
+  }
+  for (const sw of Object.values(unifiSwitches || {})) {
+    for (const d of Object.values(sw.ports || {})) {
+      swTotal++;
+      if (d.up) swUp++; else swDown++;
+      if ((d.tx_errs_rate || 0) > 0.01 || (d.rx_errs_rate || 0) > 0.01) swErrors++;
+      if (d.poe_power != null) poeDrawW += d.poe_power;
+      if (d.poe_max_power != null) poeMaxW += d.poe_max_power;
+    }
+  }
+
+  const poePct = poeMaxW > 0 ? (poeDrawW / poeMaxW * 100) : null;
+  const poeBarCls = poePct >= 80 ? 'poe-bar-crit' : poePct >= 60 ? 'poe-bar-warn' : 'poe-bar-ok';
+  const totalErrors = svrErrors + swErrors;
+  const hasAlerts = totalErrors > 0 || svrFlap > 0 || swDown > 0;
+
+  return `
+    <div class="link-summary-panel${hasAlerts ? ' link-summary-has-alerts' : ''}">
+      <div class="link-summary-grid">
+        <div class="link-summary-stat">
+          <span class="lss-label">Server Ifaces</span>
+          <span class="lss-value">${svrTotal}</span>
+        </div>
+        ${svrErrors > 0 ? `<div class="link-summary-stat lss-alert">
+          <span class="lss-label">Iface Errors</span>
+          <span class="lss-value val-crit">${svrErrors}</span>
+        </div>` : ''}
+        ${svrFlap > 0 ? `<div class="link-summary-stat lss-alert">
+          <span class="lss-label">Flapping</span>
+          <span class="lss-value val-warn">${svrFlap}</span>
+        </div>` : ''}
+        ${swTotal > 0 ? `<div class="link-summary-stat">
+          <span class="lss-label">Switch Ports</span>
+          <span class="lss-value">${swUp}<span class="lss-sub">/${swTotal}</span></span>
+        </div>` : ''}
+        ${swDown > 0 ? `<div class="link-summary-stat lss-alert">
+          <span class="lss-label">Ports Down</span>
+          <span class="lss-value val-crit">${swDown}</span>
+        </div>` : ''}
+        ${swErrors > 0 ? `<div class="link-summary-stat lss-alert">
+          <span class="lss-label">Port Errors</span>
+          <span class="lss-value val-crit">${swErrors}</span>
+        </div>` : ''}
+        ${poePct !== null ? `<div class="link-summary-stat">
+          <span class="lss-label">PoE Load</span>
+          <span class="lss-value ${poeBarCls === 'poe-bar-crit' ? 'val-crit' : poeBarCls === 'poe-bar-warn' ? 'val-warn' : 'val-good'}">${poeDrawW.toFixed(0)}W<span class="lss-sub">/${poeMaxW.toFixed(0)}W</span></span>
+          <div class="poe-bar-track" style="margin-top:3px"><div class="poe-bar-fill ${poeBarCls}" style="width:${poePct.toFixed(1)}%"></div></div>
+        </div>` : ''}
+        ${totalErrors === 0 && svrFlap === 0 && swDown === 0 ? `<div class="link-summary-stat">
+          <span class="lss-label">Status</span>
+          <span class="lss-value val-good">All OK ✔</span>
+        </div>` : ''}
+      </div>
+    </div>`;
+}
+
 // ── Render all hosts ──────────────────────────────────────────────
 function renderLinks(data) {
   const hosts  = data.hosts  || {};
@@ -498,6 +566,7 @@ function renderLinks(data) {
   }).join('');
 
   document.getElementById('links-container').innerHTML =
+    buildLinkSummary(hosts, unifi) +
     `<div class="link-collapse-bar">
        <button class="btn btn-secondary btn-sm" onclick="collapseAll()">Collapse all</button>
        <button class="btn btn-secondary btn-sm" onclick="expandAll()">Expand all</button>