fix(export): allow routine-only database exports

Closes #6888

apps/desktop/src/lib/export/databaseExportSelection.ts

@@ -6,3 +6,13 @@ export function buildSelectedTablesPayload(allTables: string[], selectedTables:
   const selected = new Set(selectedTables);
   return allTables.filter((table) => selected.has(table));
 }
+
+export function isDatabaseExportTableSelectionValid(options: {
+  allTableCount: number;
+  selectedTableCount: number;
+  includeStructure: boolean;
+  includeData: boolean;
+}): boolean {
+  if (!options.includeStructure && !options.includeData) return true;
+  return options.allTableCount === 0 || options.selectedTableCount > 0;
+}