feat(soak): dashboard status grid UI

Static HTML page served by DashboardServer. Renders the 2×2 room
grid with progress bars and player tiles, subscribes to WS events,
updates tiles live. Click-to-watch modal is wired but receives
frames once the CDP screencaster ships in Task 22.

Adds escapeHtml() on all user-controlled strings (roomId, player
key) — not strictly needed for our trusted bot traffic but cheap
XSS hardening against future scenarios that accept user input.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/soak/dashboard/dashboard.css

@@ -0,0 +1,173 @@
+:root {
+  --bg: #0a0e16;
+  --panel: #0e1420;
+  --border: #1a2230;
+  --text: #c8d4e4;
+  --accent: #7fbaff;
+  --good: #6fd08f;
+  --warn: #ffb84d;
+  --err: #ff5c6c;
+  --muted: #556577;
+}
+
+* { box-sizing: border-box; }
+
+body {
+  margin: 0;
+  font-family: -apple-system, system-ui, 'SF Mono', Consolas, monospace;
+  background: var(--bg);
+  color: var(--text);
+}
+
+.dash-header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  padding: 12px 20px;
+  background: linear-gradient(135deg, #0f1823, #0a1018);
+  border-bottom: 1px solid var(--border);
+}
+.dash-header h1 { margin: 0; font-size: 16px; color: var(--accent); }
+.dash-header .meta { font-size: 11px; color: var(--muted); }
+.dash-header .meta span + span { margin-left: 12px; }
+
+.meta-bar {
+  display: flex;
+  gap: 24px;
+  padding: 10px 20px;
+  background: #0c131d;
+  border-bottom: 1px solid var(--border);
+  font-size: 12px;
+}
+.meta-bar .stat .label { color: var(--muted); margin-right: 6px; }
+.meta-bar .stat span:last-child { color: #fff; font-weight: 600; }
+
+.rooms {
+  display: grid;
+  grid-template-columns: 1fr 1fr;
+  gap: 1px;
+  background: var(--border);
+}
+.room {
+  background: var(--panel);
+  padding: 14px 18px;
+  min-height: 180px;
+}
+.room-title {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  margin-bottom: 10px;
+}
+.room-title .name { font-size: 13px; color: var(--accent); font-weight: 600; }
+.room-title .phase {
+  font-size: 10px;
+  padding: 2px 8px;
+  border-radius: 10px;
+  background: #1a3a2a;
+  color: var(--good);
+}
+.room-title .phase.lobby { background: #3a2a1a; color: var(--warn); }
+.room-title .phase.err { background: #3a1a1a; color: var(--err); }
+
+.players {
+  display: grid;
+  grid-template-columns: repeat(2, 1fr);
+  gap: 4px;
+  font-size: 11px;
+  margin-bottom: 8px;
+}
+.player {
+  display: flex;
+  justify-content: space-between;
+  padding: 4px 8px;
+  background: #0a0f18;
+  border-radius: 3px;
+  cursor: pointer;
+  border: 1px solid transparent;
+}
+.player:hover { border-color: var(--accent); }
+.player.active {
+  background: #1a2a40;
+  border-left: 2px solid var(--accent);
+}
+.player .score { color: var(--muted); }
+
+.progress-bar {
+  height: 4px;
+  background: var(--border);
+  border-radius: 2px;
+  overflow: hidden;
+  margin-top: 6px;
+}
+.progress-fill {
+  height: 100%;
+  background: linear-gradient(90deg, var(--accent), var(--good));
+  transition: width 0.3s;
+}
+.room-meta {
+  font-size: 10px;
+  color: var(--muted);
+  display: flex;
+  gap: 12px;
+  margin-top: 6px;
+}
+
+.log {
+  border-top: 1px solid var(--border);
+  background: #080c13;
+  max-height: 160px;
+  overflow-y: auto;
+}
+.log .log-header {
+  padding: 6px 20px;
+  font-size: 10px;
+  text-transform: uppercase;
+  color: var(--muted);
+  border-bottom: 1px solid var(--border);
+}
+.log ul { list-style: none; margin: 0; padding: 4px 20px; font-size: 10px; }
+.log li { line-height: 1.5; font-family: monospace; color: var(--muted); }
+.log li.warn { color: var(--warn); }
+.log li.error { color: var(--err); }
+
+.video-modal {
+  position: fixed;
+  inset: 0;
+  background: rgba(0, 0, 0, 0.85);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  z-index: 100;
+}
+.video-modal.hidden { display: none; }
+.video-modal-content {
+  background: var(--panel);
+  border: 1px solid var(--border);
+  border-radius: 6px;
+  padding: 16px;
+  max-width: 90vw;
+  max-height: 90vh;
+}
+.video-modal-header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  margin-bottom: 12px;
+  color: var(--accent);
+  font-size: 13px;
+}
+.video-modal-header button {
+  background: var(--border);
+  color: var(--text);
+  border: none;
+  padding: 4px 12px;
+  border-radius: 3px;
+  cursor: pointer;
+}
+#video-frame {
+  display: block;
+  max-width: 100%;
+  max-height: 70vh;
+  border: 1px solid var(--border);
+}