feat: split seatmap admin and readonly flows

legacy/static/organization.css

@@ -1,5 +1,6 @@
 body {
   overflow-x: hidden;
+  overflow-y: hidden;
 }
 
 .org-canvas {
@@ -332,6 +333,29 @@ body {
   align-items: stretch;
 }
 
+.member-edit-layout {
+  display: grid;
+  grid-template-columns: minmax(320px, 380px) minmax(0, 1fr);
+  gap: 16px;
+  align-items: stretch;
+}
+
+.member-edit-left-pane,
+.member-edit-right-pane {
+  min-width: 0;
+}
+
+.member-edit-left-pane {
+  display: flex;
+  flex-direction: column;
+  gap: 12px;
+}
+
+.member-seat-field {
+  flex: 1 1 auto;
+  min-height: 0;
+}
+
 .member-detail-top-row {
   width: 100%;
   display: grid;
@@ -577,6 +601,10 @@ body {
     grid-template-columns: 1fr;
   }
 
+  .member-edit-layout {
+    grid-template-columns: 1fr;
+  }
+
   .member-detail-top-row,
   .member-inline-info-grid {
     grid-template-columns: 1fr;