Add governed source freshness audit

frontend/src/styles/premium.css

@@ -821,6 +821,173 @@ details.ai-lab-model-surface > summary strong {
   -webkit-line-clamp: 2;
 }
 
+.source-freshness-panel {
+  overflow: hidden;
+  border: 1px solid var(--line);
+  border-radius: 7px;
+  background: #ffffff;
+}
+
+.source-freshness-header {
+  display: flex;
+  gap: 1rem;
+  align-items: center;
+  justify-content: space-between;
+  padding: 1rem 1.2rem;
+}
+
+.source-freshness-header h2 {
+  margin: 0;
+  font-size: 1.05rem;
+}
+
+.source-freshness-header p:last-child {
+  max-width: 52rem;
+  margin: 0.3rem 0 0;
+  color: var(--muted);
+  font-size: 0.82rem;
+}
+
+.source-freshness-summary {
+  display: grid;
+  grid-template-columns: repeat(4, minmax(0, 1fr));
+  border-top: 1px solid var(--line);
+  border-bottom: 1px solid var(--line);
+  background: #f8fafb;
+}
+
+.source-freshness-summary span {
+  padding: 0.7rem 1rem;
+  border-right: 1px solid var(--line);
+  color: var(--muted);
+  font-size: 0.75rem;
+}
+
+.source-freshness-summary span:last-child {
+  border-right: 0;
+}
+
+.source-freshness-summary strong {
+  display: block;
+  margin-bottom: 0.15rem;
+  color: #24333d;
+  font-size: 1.05rem;
+}
+
+.source-freshness-attention,
+.source-freshness-list {
+  display: grid;
+}
+
+.source-freshness-row {
+  padding: 0.75rem 1rem;
+  border-bottom: 1px solid var(--line);
+}
+
+.source-freshness-row:last-child {
+  border-bottom: 0;
+}
+
+.source-freshness-row-review_required {
+  box-shadow: inset 3px 0 0 #b84e4e;
+}
+
+.source-freshness-row-due {
+  box-shadow: inset 3px 0 0 #ca7a18;
+}
+
+.source-freshness-row-current {
+  box-shadow: inset 3px 0 0 #2d9272;
+}
+
+.source-freshness-main {
+  display: flex;
+  gap: 1rem;
+  align-items: start;
+  justify-content: space-between;
+}
+
+.source-freshness-main > div {
+  display: grid;
+  gap: 0.15rem;
+}
+
+.source-freshness-main strong {
+  color: #23313b;
+  font-size: 0.86rem;
+}
+
+.source-freshness-main span,
+.source-freshness-row p,
+.source-freshness-meta {
+  color: var(--muted);
+  font-size: 0.75rem;
+}
+
+.source-freshness-row p {
+  margin: 0.4rem 0;
+}
+
+.source-freshness-status {
+  flex: 0 0 auto;
+  color: #33424d !important;
+  font-weight: 750;
+}
+
+.source-freshness-meta {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.35rem 1rem;
+}
+
+.source-freshness-ok,
+.source-freshness-limitation {
+  margin: 0;
+  padding: 0.8rem 1rem;
+  color: var(--muted);
+  font-size: 0.78rem;
+}
+
+.source-freshness-details {
+  border-top: 1px solid var(--line);
+}
+
+.source-freshness-details > summary {
+  display: flex;
+  cursor: pointer;
+  gap: 1rem;
+  justify-content: space-between;
+  padding: 0.72rem 1rem;
+  color: #33424d;
+  font-size: 0.78rem;
+  font-weight: 700;
+}
+
+.source-freshness-list {
+  max-height: 30rem;
+  overflow: auto;
+  border-top: 1px solid var(--line);
+}
+
+@media (max-width: 760px) {
+  .source-freshness-header {
+    align-items: stretch;
+    flex-direction: column;
+  }
+
+  .source-freshness-summary {
+    grid-template-columns: repeat(2, minmax(0, 1fr));
+  }
+
+  .source-freshness-summary span:nth-child(2) {
+    border-right: 0;
+  }
+
+  .source-freshness-summary span:nth-child(-n + 2) {
+    border-bottom: 1px solid var(--line);
+  }
+}
+
 .workflow-guidance-panel {
   border: 1px solid var(--line);
   border-left: 1px solid var(--line);