Address PR review feedback (#1703)

- FNXC requirement-trace comments on the stepwise workflow-step seam,
  the flowToIr v2-signal/byte-identity contract, and TaskForm's
  optional-steps create-mode behavior

packages/core/src/builtin-stepwise-coding-workflow-ir.ts

@@ -123,8 +123,12 @@ const RAW_BUILTIN_STEPWISE_CODING_WORKFLOW_IR: WorkflowIr = {
     },
     // KTD-5: rework exhaustion escalates to a manual hold (a human releases it).
     { id: "rework-hold", kind: "hold", column: "in-progress", config: { release: "manual" } },
-    // Pre-merge workflow-step seam (parity with builtin-coding-workflow-ir): the
-    // ONLY node that makes the graph invoke `runWorkflowSteps`, so a per-task
+    // FNXC:WorkflowOptionalSteps 2026-06-21-00:00:
+    // The stepwise workflow must actually run a task's enabled optional steps (e.g.
+    // browser verification), so it needs the same pre-merge workflow-step seam the
+    // coding workflow has — declaring the optional step without this node would be a
+    // dead toggle. Pre-merge workflow-step seam (parity with builtin-coding-workflow-ir):
+    // the ONLY node that makes the graph invoke `runWorkflowSteps`, so a per-task
     // `enabledWorkflowSteps` (e.g. the optional browser-verification step declared
     // below) actually executes. Runs ONCE after the foreach completes, between
     // implementation and review — not per step-instance.

packages/dashboard/app/components/TaskForm.tsx

@@ -295,6 +295,10 @@ export function TaskForm({
       .catch(() => setGlobalSettings(null));
   }, [isActive, projectId, onWorkflowIdChange]);
 
+  // FNXC:WorkflowOptionalSteps 2026-06-21-00:00:
+  // Creating a task should let the user opt into the selected workflow's optional
+  // steps, seeded from each step's defaultOn. TaskForm fetches + seeds these in
+  // create mode and lifts the enabled set to NewTaskModal for the create payload.
   // Optional workflow steps for the currently-selected workflow (create mode only).
   // `null` selection ("No workflow") → no steps; `undefined` → project default.
   const effectiveOptionalWorkflowId =

packages/dashboard/app/components/workflow-flow-mapping.ts

@@ -456,9 +456,12 @@ export function flowToIr(
   const hasFields = Array.isArray(fields) && fields.length > 0;
   const hasSettings = Array.isArray(settings) && settings.length > 0;
   const hasOptionalSteps = Array.isArray(optionalSteps) && optionalSteps.length > 0;
-  // Fields, settings, and optional steps are v2-only declarations: a workflow with
-  // any of them but no custom columns still serializes as v2 (with the synthesized
-  // default columns). Empty/absent → not a v2 signal (R6 byte-identity).
+  // FNXC:WorkflowOptionalSteps 2026-06-21-00:00:
+  // Optional steps must round-trip through the node editor without data loss, yet
+  // must never upgrade a legacy v1 graph. Fields, settings, and optional steps are
+  // v2-only declarations: a workflow with any of them but no custom columns still
+  // serializes as v2 (with the synthesized default columns). Empty/absent → not a
+  // v2 signal, and the key is omitted entirely (R6 byte-identity for legacy graphs).
   const v2 =
     (Array.isArray(columns) && columns.length > 0) || hasFields || hasSettings || hasOptionalSteps;
   const layout: Record<string, { x: number; y: number }> = {};