feat(ext/popup): devices view — list devices with revoke actions

Shows registered devices with "← you" indicator on current device.
Revoke button on other devices. Unregistered banner if current
device not in list.

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

extension/src/popup/styles.css

@@ -1060,3 +1060,76 @@ textarea {
   opacity: 0.5;
   cursor: default;
 }
+
+/* --- Devices view --- */
+
+.devices-header {
+  display: flex;
+  align-items: center;
+  gap: 12px;
+  margin-bottom: 12px;
+}
+
+.device-banner {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 8px;
+  padding: 10px;
+  background: #3d1f00;
+  border: 1px solid #9e6a03;
+  border-radius: 4px;
+  margin-bottom: 12px;
+  font-size: 12px;
+  color: #f0c674;
+}
+
+.device-row {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  padding: 10px;
+  border-radius: 4px;
+  background: #161b22;
+  margin-bottom: 6px;
+}
+
+.device-row__info {
+  flex: 1;
+  min-width: 0;
+}
+
+.device-row__name {
+  display: block;
+  font-size: 13px;
+  color: #c9d1d9;
+}
+
+.device-row__you {
+  font-size: 11px;
+  color: #58a6ff;
+}
+
+.device-row__meta {
+  font-size: 11px;
+  color: #8b949e;
+}
+
+.device-row__revoke {
+  font-size: 11px;
+  padding: 4px 8px;
+  background: #da3633;
+  color: #fff;
+  border: none;
+  border-radius: 4px;
+  cursor: pointer;
+}
+
+.device-row__revoke:hover {
+  background: #f85149;
+}
+
+.device-row__revoke:disabled {
+  opacity: 0.5;
+  cursor: default;
+}