Add AI lab action guardrails

frontend/src/components/segmentation/SegmentationLab.tsx

@@ -90,8 +90,19 @@ export function SegmentationLab({
 }: SegmentationLabProps): JSX.Element {
   const segmentationHasDataset = selectedSegmentationDatasetId.length > 0
   const segmentationHasTileManifest = segmentationTileManifestPath.trim().length > 0
+  const segmentationModelUiRunnable =
+    selectedSegmentationModelConfigured && selectedSegmentationModelId !== 'fixture-segmenter'
   const segmentationRunReady =
-    Boolean(selectedProjectId) && segmentationHasDataset && selectedSegmentationModelConfigured
+    Boolean(selectedProjectId) && segmentationHasDataset && segmentationModelUiRunnable
+  const segmentationRunBlockedReason = !selectedProjectId
+    ? 'Select or create a project first'
+    : !segmentationHasDataset
+      ? 'Select a raster dataset'
+      : selectedSegmentationModelId === 'fixture-segmenter'
+        ? 'Fixture segmenter is explicit test/demo-only'
+        : !selectedSegmentationModelConfigured
+          ? selectedSegmentationModelLimitation ?? 'Selected segmentation model is not configured'
+          : null
 
   return (
     <section className="workspace-panel ai-lab-shell segmentation-lab-shell">
@@ -184,6 +195,10 @@ export function SegmentationLab({
               </div>
             </div>
           </div>
+          <div className={segmentationRunReady ? 'lab-action-guardrail lab-action-guardrail-ready' : 'lab-action-guardrail'}>
+            <span>Run action</span>
+            <strong>{segmentationRunReady ? 'Ready to submit a segmentation job' : segmentationRunBlockedReason}</strong>
+          </div>
           {rasterDatasets.length === 0 ? (
             <div className="result-state result-state-empty">
               <strong>No raster datasets available for segmentation.</strong>
@@ -237,7 +252,7 @@ export function SegmentationLab({
             className="primary-action"
             type="button"
             onClick={onRunSegmentation}
-            disabled={runningSegmentation || !selectedProjectId || rasterDatasets.length === 0 || !selectedSegmentationModelConfigured}
+            disabled={runningSegmentation || !segmentationRunReady}
           >
             Run segmentation
           </button>