Add datasource quality and schema gates

webui/src/styles/datasources.css

@@ -369,6 +369,74 @@
   font-weight: 600;
 }
 
+.datasources-validation-alerts {
+  display: grid;
+  gap: 8px;
+  padding: 10px;
+  border-top: var(--border-line);
+}
+
+.datasources-validation-alerts .alert {
+  margin: 0;
+}
+
+.datasources-diagnostic-list,
+.datasources-schema-changes {
+  display: grid;
+  gap: 7px;
+  margin: 7px 0 0;
+  padding: 0;
+  list-style: none;
+}
+
+.datasources-diagnostic-list li,
+.datasources-diagnostic-list span,
+.datasources-diagnostic-list small,
+.datasources-schema-changes li,
+.datasources-schema-changes span,
+.datasources-schema-changes strong,
+.datasources-schema-changes small {
+  display: block;
+  min-width: 0;
+}
+
+.datasources-diagnostic-list small,
+.datasources-schema-changes small {
+  margin-top: 2px;
+  color: var(--muted);
+  font-size: 11px;
+}
+
+.datasources-validation-ok {
+  padding: 10px 12px;
+  border-top: var(--border-line);
+  color: var(--success);
+  font-size: 12px;
+}
+
+.datasources-schema-changes {
+  margin: 0;
+  padding: 8px 10px;
+}
+
+.datasources-schema-changes li {
+  display: grid;
+  grid-template-columns: auto minmax(0, 1fr);
+  align-items: start;
+  gap: 9px;
+  padding: 6px 0;
+}
+
+.datasources-schema-changes li + li {
+  border-top: var(--border-line);
+}
+
+.datasources-schema-changes strong {
+  color: var(--text-strong);
+  font-size: 12px;
+  font-weight: 600;
+}
+
 .datasources-workspace-empty {
   display: grid;
   place-items: center;