Polish export handoff artifacts

frontend/src/styles/app.css

@@ -1831,6 +1831,7 @@ button.entity-card {
 
 .export-summary-surface,
 .export-handoff-surface,
+.latest-artifact-surface,
 .export-actions-surface,
 .export-history-surface,
 .system-provider-capability-surface {
@@ -1849,6 +1850,10 @@ button.entity-card {
   background: #ffffff;
 }
 
+.latest-artifact-surface {
+  background: #ffffff;
+}
+
 .export-center-shell .quality-summary-grid {
   display: grid;
   grid-template-columns: repeat(auto-fit, minmax(8rem, 1fr));
@@ -1977,6 +1982,69 @@ button.entity-card {
   margin-top: 0;
 }
 
+.latest-artifact-grid {
+  display: grid;
+  grid-template-columns: repeat(auto-fit, minmax(12rem, 1fr));
+  gap: 0.6rem;
+}
+
+.latest-artifact-card {
+  display: grid;
+  min-width: 0;
+  gap: 0.36rem;
+  border: 1px solid rgba(15, 118, 110, 0.2);
+  border-radius: 8px;
+  padding: 0.72rem;
+  background: linear-gradient(180deg, #f8fcfa, #ffffff);
+}
+
+.latest-artifact-card-empty {
+  border-style: dashed;
+  border-color: var(--line);
+  background: var(--panel-soft);
+}
+
+.latest-artifact-card span {
+  color: var(--muted);
+  font-size: 0.68rem;
+  font-weight: 850;
+  letter-spacing: 0.05em;
+  text-transform: uppercase;
+}
+
+.latest-artifact-card strong {
+  overflow: hidden;
+  font-size: 0.9rem;
+  line-height: 1.24;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.latest-artifact-card p,
+.latest-artifact-card small {
+  margin: 0;
+  color: var(--muted);
+  font-size: 0.8rem;
+  line-height: 1.35;
+  overflow-wrap: anywhere;
+}
+
+.latest-artifact-actions {
+  display: grid;
+  grid-template-columns: repeat(2, minmax(0, 1fr));
+  gap: 0.45rem;
+  align-items: center;
+  margin-top: 0.18rem;
+}
+
+.latest-artifact-actions button,
+.latest-artifact-actions .status-badge {
+  width: 100%;
+  min-height: 2.1rem;
+  justify-content: center;
+  text-align: center;
+}
+
 .export-type-badge {
   display: inline-flex;
   max-width: 100%;