feat(client): track digital sync retry history

qimingclaw/crates/agent-electron-client/embedded/sgrobot-digital/src/index.css

@@ -1698,6 +1698,59 @@
   font-size: 13px;
   line-height: 1.55;
 }
+.de-sync-attempt-history {
+  display: grid;
+  gap: 8px;
+  padding: 14px;
+  border: 1px solid rgba(126,163,194,0.2);
+  border-radius: 14px;
+  background: rgba(247,251,255,0.82);
+}
+.de-sync-attempt-history > span {
+  color: #6f8196;
+  font-size: 12px;
+  font-weight: 800;
+}
+.de-sync-attempt-list {
+  display: grid;
+  gap: 8px;
+}
+.de-sync-attempt-row {
+  display: grid;
+  gap: 5px;
+  padding: 9px 10px;
+  border-radius: 12px;
+  background: rgba(255,255,255,0.72);
+}
+.de-sync-attempt-row > div {
+  display: flex;
+  align-items: center;
+  flex-wrap: wrap;
+  gap: 8px;
+}
+.de-sync-attempt-row strong {
+  color: #153754;
+  font-size: 12px;
+}
+.de-sync-attempt-row em {
+  font-size: 12px;
+  font-style: normal;
+  font-weight: 800;
+}
+.de-sync-attempt-row span,
+.de-sync-attempt-row small {
+  color: #667b90;
+  font-size: 12px;
+}
+.de-sync-attempt-row small {
+  line-height: 1.45;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+.de-sync-attempt-row--success em { color: #23805d; }
+.de-sync-attempt-row--danger em { color: #bb3b3b; }
+.de-sync-attempt-row--info em { color: #2e6fa5; }
 .de-event-modal-actions {
   display: flex;
   justify-content: flex-end;