feat: Verbindungsdetails Modal mit Live-Ping

- Backend: Voice-Stats (Ping, Gateway, Status, Uptime) via SSE alle 5s
- Frontend: Klick auf Verbunden oeffnet Modal mit allen Verbindungsdetails
- Ping-Anzeige direkt im Header neben Verbunden
- Farbcodierte Ping-Dots (gruen <80ms, gelb <150ms, rot >=150ms)
- Uptime-Zaehler seit letztem VoiceConnection Ready
- connectedSince Tracking pro Guild

web/src/styles.css

@@ -353,6 +353,90 @@ input, select {
   50% { box-shadow: 0 0 12px rgba(35, 165, 90, .8); }
 }
 
+.conn-ping {
+  font-size: 10px;
+  opacity: .7;
+  margin-left: 2px;
+}
+
+/* ── Connection Details Modal ── */
+.conn-modal-overlay {
+  position: fixed;
+  inset: 0;
+  background: rgba(0, 0, 0, .55);
+  z-index: 9000;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  backdrop-filter: blur(4px);
+  animation: fadeIn .15s ease;
+}
+.conn-modal {
+  background: var(--card);
+  border: 1px solid var(--border);
+  border-radius: 16px;
+  width: 340px;
+  box-shadow: 0 20px 60px rgba(0,0,0,.4);
+  overflow: hidden;
+  animation: slideUp .2s ease;
+}
+@keyframes slideUp {
+  from { transform: translateY(20px); opacity: 0; }
+  to { transform: translateY(0); opacity: 1; }
+}
+.conn-modal-header {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  padding: 14px 16px;
+  border-bottom: 1px solid var(--border);
+  font-weight: 700;
+  font-size: 14px;
+}
+.conn-modal-close {
+  margin-left: auto;
+  background: none;
+  border: none;
+  color: var(--muted);
+  cursor: pointer;
+  padding: 4px;
+  border-radius: 6px;
+  display: flex;
+  transition: all .15s;
+}
+.conn-modal-close:hover {
+  background: rgba(255,255,255,.08);
+  color: var(--fg);
+}
+.conn-modal-body {
+  padding: 16px;
+  display: flex;
+  flex-direction: column;
+  gap: 12px;
+}
+.conn-stat {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+}
+.conn-stat-label {
+  color: var(--muted);
+  font-size: 13px;
+}
+.conn-stat-value {
+  font-weight: 600;
+  font-size: 13px;
+  display: flex;
+  align-items: center;
+  gap: 6px;
+}
+.conn-ping-dot {
+  width: 8px;
+  height: 8px;
+  border-radius: 50%;
+  flex-shrink: 0;
+}
+
 /* ── Admin Icon Button ── */
 .admin-btn-icon {
   width: 32px;