Add raw GVL evidence storage and restore evidence purge UI

src/popup/popup.css

@@ -175,3 +175,45 @@ button:disabled {
   cursor: default;
   opacity: 0.65;
 }
+
+.confirm-modal {
+  position: fixed;
+  inset: 0;
+  display: grid;
+  place-items: center;
+  padding: 14px;
+  background: rgba(15, 23, 42, 0.72);
+}
+
+.confirm-modal[hidden] {
+  display: none;
+}
+
+.confirm-modal-panel {
+  display: grid;
+  gap: 10px;
+  width: min(100%, 320px);
+  padding: 12px;
+  border: 1px solid #475569;
+  border-radius: 6px;
+  color: #e5edf5;
+  background: #111827;
+  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.35);
+}
+
+.confirm-modal-panel h2 {
+  margin: 0;
+  font-size: 14px;
+}
+
+.confirm-modal-panel p {
+  margin: 0;
+  font-size: 12px;
+  line-height: 1.4;
+  color: #cbd5e1;
+}
+
+.confirm-modal-actions {
+  display: grid;
+  gap: 8px;
+}