fix #495: add schema preflight and DDL details

src/main/resources/static/css/app.css

@@ -1098,6 +1098,85 @@ body {
   white-space: pre-wrap;
 }
 
+.schema-summary {
+  display: grid;
+  gap: .75rem;
+  grid-template-columns: repeat(6, minmax(0, 1fr));
+}
+
+.schema-summary div {
+  background: var(--rw-surface-muted);
+  border: 1px solid var(--rw-border);
+  border-radius: 8px;
+  min-width: 0;
+  padding: .7rem .8rem;
+}
+
+.schema-summary span {
+  color: var(--rw-muted);
+  display: block;
+  font-size: .76rem;
+  line-height: 1.35;
+}
+
+.schema-summary strong {
+  color: var(--rw-text);
+  display: block;
+  font-size: .98rem;
+  font-weight: 800;
+  line-height: 1.35;
+  overflow-wrap: anywhere;
+}
+
+.schema-preview-grid {
+  display: grid;
+  gap: 1rem;
+  grid-template-columns: repeat(2, minmax(0, 1fr));
+}
+
+.schema-preview-grid details {
+  border: 1px solid var(--rw-border);
+  border-radius: 8px;
+  min-width: 0;
+}
+
+.schema-preview-grid summary {
+  cursor: pointer;
+  font-weight: 800;
+  padding: .75rem .9rem;
+}
+
+.schema-sql-preview {
+  background: #211f1d;
+  border-top: 1px solid var(--rw-border);
+  color: #fbf9f7;
+  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
+  font-size: .76rem;
+  line-height: 1.45;
+  margin: 0;
+  max-height: 28rem;
+  overflow: auto;
+  padding: .85rem;
+  white-space: pre-wrap;
+  word-break: break-word;
+}
+
+.table-responsive > .schema-preflight-table th,
+.table-responsive > .schema-preflight-table td,
+.table-responsive > .schema-preflight-table code {
+  overflow-wrap: anywhere;
+  white-space: normal;
+}
+
+.schema-preflight-table th:nth-child(1),
+.schema-preflight-table td:nth-child(1),
+.schema-preflight-table th:nth-child(3),
+.schema-preflight-table td:nth-child(3),
+.schema-preflight-table th:nth-child(4),
+.schema-preflight-table td:nth-child(4) {
+  width: 8rem;
+}
+
 .policy-function-button {
   border-radius: 8px;
   max-width: 100%;
@@ -1329,6 +1408,14 @@ body {
 }
 
 @media (max-width: 920px) {
+  .schema-summary {
+    grid-template-columns: repeat(3, minmax(0, 1fr));
+  }
+
+  .schema-preview-grid {
+    grid-template-columns: 1fr;
+  }
+
   .architecture-strip {
     grid-template-columns: 1fr;
   }
@@ -1339,6 +1426,10 @@ body {
 }
 
 @media (max-width: 640px) {
+  .schema-summary {
+    grid-template-columns: repeat(2, minmax(0, 1fr));
+  }
+
   main.container {
     max-width: 100%;
     min-width: 0;