feat: catalog audit can repair orphaned refs and duplicate classnames

- add repairOrphanedCatalog: remove catalog_items rows whose item_ids only
  reference missing items_base entries, strip orphaned ids from mixed rows
- add repairDuplicateClassnames: merge items_base duplicates into one
  canonical row per classname, remap references, delete duplicate rows
- add 'repair structural issues' checkbox + result display in audit UI

src/app/admin/import/audit/audit-client.tsx

@@ -48,6 +48,11 @@ interface AuditSummary {
 	catalogSqlApplied: number;
 	furniDataAdded: number;
 	furniDataDuplicatesRemoved: number;
+	orphanedRemoved: number;
+	orphanedCleaned: number;
+	duplicatesMerged: number;
+	duplicateRowsRemoved: number;
+	remappedReferences: number;
 }
 
 interface RepairStats {
@@ -73,6 +78,13 @@ interface AuditEvent {
 	applied?: number;
 	sqlFailed?: number;
 	furniData?: { added: number; removedDuplicates: number };
+	structure?: {
+		orphanedRemoved: number;
+		orphanedCleaned: number;
+		duplicatesMerged: number;
+		duplicateRowsRemoved: number;
+		remappedReferences: number;
+	};
 }
 
 const TYPE_LABELS: Record<string, string> = {
@@ -131,6 +143,7 @@ export function AuditClient() {
 	const [generateSql, setGenerateSql] = useState(false);
 	const [applySql, setApplySql] = useState(false);
 	const [repairFurniData, setRepairFurniData] = useState(false);
+	const [repairStructure, setRepairStructure] = useState(false);
 
 	const [issues, setIssues] = useState<AuditIssue[]>([]);
 	const [missingFromSources, setMissingFromSources] = useState<
@@ -150,6 +163,13 @@ export function AuditClient() {
 		added: number;
 		removedDuplicates: number;
 	} | null>(null);
+	const [structureResult, setStructureResult] = useState<{
+		orphanedRemoved: number;
+		orphanedCleaned: number;
+		duplicatesMerged: number;
+		duplicateRowsRemoved: number;
+		remappedReferences: number;
+	} | null>(null);
 
 	const [checkProgress, setCheckProgress] = useState<{
 		section: string;
@@ -170,6 +190,7 @@ export function AuditClient() {
 		setSqlText(null);
 		setSqlApplied(null);
 		setFurniDataResult(null);
+		setStructureResult(null);
 		setCheckProgress(null);
 		setActiveTab("issues");
 
@@ -187,6 +208,7 @@ export function AuditClient() {
 					sql: generateSql || applySql,
 					applySql,
 					repairFurniData,
+					repairStructure,
 				}),
 			});
 
@@ -267,6 +289,10 @@ export function AuditClient() {
 							if (evt.furniData) setFurniDataResult(evt.furniData);
 						}
 
+						if (evt.type === "structure_repair_complete") {
+							if (evt.structure) setStructureResult(evt.structure);
+						}
+
 						if (evt.type === "batch_complete") {
 							setIssues(evt.issues ?? []);
 							setMissingFromSources(evt.missingFromSources ?? []);
@@ -309,7 +335,14 @@ export function AuditClient() {
 			setLoading(false);
 			abortRef.current = null;
 		}
-	}, [repairEnabled, repairNitros, generateSql, applySql, repairFurniData]);
+	}, [
+		repairEnabled,
+		repairNitros,
+		generateSql,
+		applySql,
+		repairFurniData,
+		repairStructure,
+	]);
 
 	const errors = issues.filter((i) => i.severity === "error");
 	const warnings = issues.filter((i) => i.severity === "warning");
@@ -372,6 +405,13 @@ export function AuditClient() {
 					>
 						Repair FurnitureData.json (add missing + dedupe)
 					</AuditCheckbox>
+					<AuditCheckbox
+						checked={repairStructure}
+						disabled={loading}
+						onChange={setRepairStructure}
+					>
+						Repair structural issues (orphaned refs + duplicates)
+					</AuditCheckbox>
 					{loading && (
 						<Button
 							variant="outline"
@@ -601,6 +641,49 @@ export function AuditClient() {
 								</span>
 							</div>
 						)}
+						{structureResult && (
+							<div className="flex items-center gap-2 col-span-full">
+								<span className="text-xs text-muted-foreground">
+									Structural repair:{" "}
+									{structureResult.orphanedRemoved > 0 && (
+										<>
+											<span className="text-[var(--admin-success)] font-medium">
+												{structureResult.orphanedRemoved} orphaned rows removed
+											</span>
+											{" · "}
+										</>
+									)}
+									{structureResult.orphanedCleaned > 0 && (
+										<>
+											<span className="font-medium">
+												{structureResult.orphanedCleaned} cleaned
+											</span>
+											{" · "}
+										</>
+									)}
+									{structureResult.duplicatesMerged > 0 && (
+										<>
+											<span className="text-[var(--admin-success)] font-medium">
+												{structureResult.duplicatesMerged} classname(s) merged
+											</span>
+											{" · "}
+										</>
+									)}
+									{structureResult.duplicateRowsRemoved > 0 && (
+										<>
+											<span className="text-[var(--admin-warning)] font-medium">
+												{structureResult.duplicateRowsRemoved} duplicate rows
+												removed
+											</span>
+											{" · "}
+										</>
+									)}
+									<span className="text-[var(--admin-text-muted)]">
+										{structureResult.remappedReferences} reference(s) remapped
+									</span>
+								</span>
+							</div>
+						)}
 					</div>
 
 					{/* Tabs */}
@@ -733,6 +816,7 @@ export function AuditClient() {
 							setSqlText(null);
 							setSqlApplied(null);
 							setFurniDataResult(null);
+							setStructureResult(null);
 							setProgress("");
 							setCheckProgress(null);
 						}}