feat: complete catalog-driven preprocessing

frontend/src/api/client.ts

@@ -38,6 +38,7 @@ const safeErrorCodes = new Set([
   "relationship_not_found", "relationship_duplicate", "relationship_target_not_unique",
   "relationship_type_incompatible", "relationship_read_only", "relationship_request_invalid",
   "relationship_operation_failed", "relationship_schema_stale", "column_not_found",
+  "preprocessing_request_invalid", "preprocessing_blocked", "preprocessing_run_failed",
 ]);
 
 type SafeErrorPayload = {
@@ -116,6 +117,9 @@ const localCodeMessages: Record<string, string> = {
   relationship_operation_failed: "The relationship operation failed.",
   relationship_schema_stale: "Synchronize the current database schema before managing logical relationships.",
   column_not_found: "The selected catalog column was not found. Refresh and try again.",
+  preprocessing_request_invalid: "The preprocessing request is invalid.",
+  preprocessing_blocked: "Preprocessing is blocked by a current workspace prerequisite.",
+  preprocessing_run_failed: "Preprocessing failed. Review the latest diagnostic and retry.",
 };
 
 const localStatusMessages: Record<number, string> = {