feat(workflow-executor): add 3-way execution mode to the load related record step (PRD-148)

packages/workflow-executor/src/errors.ts

@@ -270,6 +270,17 @@ export class AiInvokeTimeoutError extends WorkflowExecutorError {
   }
 }
 
+// Wraps any AI-call failure (timeout, outage, malformed/missing tool call, out-of-range pick) so
+// handlers degrade to the Manual path. Caught internally — never HTTP-mapped; not exported from index.
+export class AiAssistUnavailableError extends WorkflowExecutorError {
+  readonly reason: unknown;
+
+  constructor(reason: unknown) {
+    super('AI assistance unavailable');
+    this.reason = reason;
+  }
+}
+
 export class NoMcpToolsError extends WorkflowExecutorError {
   constructor(requestedMcpServerId: string) {
     super(

packages/workflow-executor/src/http/step-serializer.ts

@@ -15,9 +15,12 @@ export default function serializeStepForWire(step: StepExecutionData): unknown {
       return { ...step, selectedRecordRef: serializeRecordRef(step.selectedRecordRef) };
 
     case 'load-related-record': {
+      // Omit selectedRecordRef when absent — serializing undefined throws.
       const result: Record<string, unknown> = {
         ...step,
-        selectedRecordRef: serializeRecordRef(step.selectedRecordRef),
+        ...(step.selectedRecordRef && {
+          selectedRecordRef: serializeRecordRef(step.selectedRecordRef),
+        }),
       };
 
       if (step.pendingData) {

packages/workflow-executor/src/types/step-execution-data.ts

@@ -176,14 +176,18 @@ export interface LoadRelatedRecordPendingData {
   availableRecordIds: LoadRelatedRecordCandidate[];
   // Absent when the relation has no linked record(s): the list is empty and there's nothing to suggest.
   suggestedRecord?: LoadRelatedRecordCandidate;
+  // The AI actively judged no candidate relevant (incl. Full AI degrading to confirmation) → the front
+  // pre-checks "No X to load". Distinct from a plain absent suggestedRecord (Manual: the user picks).
+  suggestNoRecord?: boolean;
 }
 
 export interface LoadRelatedRecordStepExecutionData
   extends BaseStepExecutionData,
     WithUserConfirmation<LoadRelatedRecordConfirmation> {
   type: 'load-related-record';
   pendingData?: LoadRelatedRecordPendingData;
-  selectedRecordRef: RecordRef;
+  // Set on every await/load path (and preserved through the user-initiated "continue without" skip).
+  selectedRecordRef?: RecordRef;
   executionParams?: RelationRef;
   executionResult?: { relation: RelationRef; record: RecordRef } | { skipped: true };
 }

packages/workflow-executor/src/types/validated/step-definition.ts

@@ -98,10 +98,10 @@ export type TriggerActionStepDefinition = z.infer<typeof TriggerActionStepDefini
 export const LoadRelatedRecordStepDefinitionSchema = z.object({
   ...sharedFields,
   type: z.literal(StepType.LoadRelatedRecord),
+  // No `.catch`: it would silently coerce `manual` to AutomatedWithConfirmation (AI prefill back on).
   executionType: z
-    .enum([AutomatedWithConfirmation, FullyAutomated])
-    .default(AutomatedWithConfirmation)
-    .catch(AutomatedWithConfirmation),
+    .enum([Manual, AutomatedWithConfirmation, FullyAutomated])
+    .default(AutomatedWithConfirmation),
   preRecordedArgs: z
     .object({
       /**