Add curator roles/permissions with Users admin, and fix lineage branch joins.

Staff accounts use admin/curator roles and fine-grained flags; transitions connect source-to-target with color gradients and stream cutout masks so overlaps stay seamless.

Co-authored-by: Cursor <cursoragent@cursor.com>

client/src/components/PaintingDetail.tsx

@@ -22,6 +22,8 @@ interface Props {
   onArtistBio: () => void;
   onInfluenceArtistClick?: (artistId: number) => void;
   isCurator?: boolean;
+  /** When false, hide the Checked action (needs checkup permission). Defaults to true when debugMode is on. */
+  canCheckup?: boolean;
   debugMode?: boolean;
   debugShowMore?: boolean;
   onPaintingImageFixed?: (
@@ -206,6 +208,7 @@ export default function PaintingDetailView({
   onArtistBio,
   onInfluenceArtistClick,
   isCurator = false,
+  canCheckup = true,
   debugMode = false,
   debugShowMore = false,
   onPaintingImageFixed,
@@ -734,14 +737,16 @@ export default function PaintingDetailView({
             <p className="debug-image-status">No Google image result found.</p>
           )}
           <div className="debug-action-buttons">
-            <button
-              type="button"
-              className="debug-checked-btn"
-              onClick={handleMarkChecked}
-              disabled={!!painting.checkup_checked || markingChecked || uploading}
-            >
-              {markingChecked ? '…' : 'Checked'}
-            </button>
+            {canCheckup && (
+              <button
+                type="button"
+                className="debug-checked-btn"
+                onClick={handleMarkChecked}
+                disabled={!!painting.checkup_checked || markingChecked || uploading}
+              >
+                {markingChecked ? '…' : 'Checked'}
+              </button>
+            )}
             <button
               type="button"
               className="debug-fix-btn"