Fix union SQL and selection previews

webui/scripts/test-dataflow-page-structure.mjs

@@ -11,6 +11,22 @@ const checks = [
   [page.includes("Apply SQL"), "SQL workbench"],
   [page.includes("<NodeInspector"), "node inspector"],
   [page.includes("previewDataflowPipeline"), "preview action"],
+  [
+    page.includes('inactiveLabel="Manual"')
+      && page.includes('activeLabel="Auto"')
+      && page.includes("void runPreview(selectedNodeId, true)"),
+    "selection-driven automatic and manual preview modes"
+  ],
+  [
+    !page.includes('aria-label="Preview stage"')
+      && page.includes('className="dataflow-preview-stage"'),
+    "selected-node preview stage without dropdown"
+  ],
+  [
+    page.includes('resetKey={error} floating')
+      && !css.includes(".dataflow-alerts"),
+    "central floating dismissible alerts"
+  ],
   [page.includes("useUnsavedDraftGuard"), "unsaved-change guard"],
   [canvas.includes("application/x-govoplan-dataflow-node"), "palette drop handling"],
   [canvas.includes("isValidConnection"), "edge validation"],
@@ -20,6 +36,11 @@ const checks = [
   [canvas.includes("onReconnect={onReconnect}"), "edge reconnection"],
   [canvas.includes("onReconnectEnd="), "edge deletion on dropped reconnection"],
   [canvas.includes("selectedEdgeId"), "persistent edge selection"],
+  [
+    canvas.includes("newGraphEdgeId()")
+      && interactions.includes("return `edge-${crypto.randomUUID()}`"),
+    "bounded opaque edge identifiers"
+  ],
   [
     canvas.includes("closestProximityConnection")
       && interactions.includes("definitionConnectionError"),