dashboard changes for Session tab

coordinator/static/dashboard.css

@@ -450,6 +450,59 @@ th.group-active { color: var(--green-hi); cursor: pointer; }
 th.group-col    { cursor: pointer; }
 th.group-col:hover { color: var(--text); }
 .nodes-multi { color: var(--green-hi); }
+.mono        { font-family: monospace; font-size: 11px; }
+
+/* ── Sessions ── */
+.sev-attack    { border-left: 2px solid #c0392b; }
+.sev-suspicious { border-left: 2px solid #d4ac0d; }
+.sev-normal    { border-left: 2px solid transparent; }
+
+.sev-label          { font-size: 10px; font-weight: 500; letter-spacing: 0.06em; text-transform: uppercase; }
+.sev-label.sev-attack     { color: #e74c3c; }
+.sev-label.sev-suspicious { color: #f1c40f; }
+.sev-label.sev-normal     { color: var(--text-muted); }
+
+tr.session-row { cursor: pointer; }
+tr.session-row:hover td { background: var(--bg-hover); }
+
+.expand-col  { width: 24px; text-align: center; }
+.expand-btn  { font-size: 9px; color: var(--text-muted); user-select: none; }
+
+td.session-detail-cell { padding: 0; }
+.session-detail-inner  {
+  padding: 10px 16px 12px;
+  background: var(--bg-panel);
+  border-top: 1px solid var(--border);
+}
+.session-meta {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 16px;
+  font-size: 11px;
+  color: var(--text-dim);
+  margin-bottom: 8px;
+}
+.session-meta strong { color: var(--text); }
+
+.session-events-table {
+  width: 100%;
+  border-collapse: collapse;
+  font-size: 11px;
+}
+.session-events-table th {
+  text-align: left;
+  color: var(--text-muted);
+  font-weight: 400;
+  padding: 3px 8px;
+  border-bottom: 1px solid var(--border);
+}
+.session-events-table td {
+  padding: 3px 8px;
+  border-bottom: 1px solid var(--border);
+  color: var(--text-dim);
+}
+.session-events-table tr:last-child td { border-bottom: none; }
+
 
 /* ── Cross-node cells ── */
 .cn-best { color: var(--green-hi); font-weight: 500; }