FN-6025: fix builtin coding auto-merge review flags

Restore the built-in coding workflow's in-review auto-merge metadata.

- switch builtin:coding to the authored v2 workflow IR so in-review retains merge-blocker and human-review traits
- add core regression coverage for builtin workflow resolution and column flag propagation
- extend dashboard board workflow route/payload tests to assert the in-review flags and payload contents

Files changed:
 .changeset/fn-6025-auto-merge-toggle-flags.md       |  5 +++++
 packages/core/src/__tests__/builtin-workflows.test.ts    | 19 +++++++++++++++++++
 packages/core/src/__tests__/workflow-ir-resolver.test.ts | 14 ++++++++++++++
 packages/core/src/builtin-workflows.ts              | 21 ++++++++++++++-------
 packages/dashboard/src/routes/__tests__/board-workflows-route.test.ts  | 12 ++++++++++--
 packages/dashboard/src/routes/__tests__/board-workflows.test.ts    |  4 ++++
 6 files changed, 66 insertions(+), 9 deletions(-)

Fusion-Task-Id: FN-6025

Fusion-Task-Lineage: 838ced1f-0fdf-413b-94a0-52ddb21d75c9

packages/core/src/__tests__/builtin-workflows.test.ts

@@ -2,6 +2,7 @@ import { describe, it, expect, beforeEach, afterEach } from "vitest";
 
 import { BUILTIN_WORKFLOWS, getBuiltinWorkflow, isBuiltinWorkflowId } from "../builtin-workflows.js";
 import { BUILTIN_CODING_WORKFLOW_IR } from "../builtin-coding-workflow-ir.js";
+import { resolveColumnFlags } from "../trait-registry.js";
 import { compileWorkflowToSteps } from "../workflow-compiler.js";
 import { DEFAULT_WORKFLOW_COLUMN_IDS, parseWorkflowIr, serializeWorkflowIr } from "../workflow-ir.js";
 import { createTaskStoreTestHarness } from "./store-test-helpers.js";
@@ -86,6 +87,24 @@ describe("built-in workflows", () => {
     ]);
   });
 
+  it("builtin:coding exposes merge-blocker and human-review traits on in-review", () => {
+    const coding = getBuiltinWorkflow("builtin:coding");
+    expect(coding).toBeDefined();
+    const ir = parseWorkflowIr(coding!.ir);
+    expect(ir.version).toBe("v2");
+    if (ir.version !== "v2") throw new Error("expected v2");
+
+    const inReview = ir.columns.find((column) => column.id === "in-review");
+    expect(inReview).toBeDefined();
+    expect(inReview!.traits.length).toBeGreaterThan(0);
+    expect(inReview!.traits.map((trait) => trait.trait)).toContain("merge-blocker");
+    expect(inReview!.traits.map((trait) => trait.trait)).toContain("human-review");
+
+    const flags = resolveColumnFlags(inReview!);
+    expect(flags.mergeBlocker).toBe(true);
+    expect(flags.humanReview).toBe(true);
+  });
+
   it("includes a coding and a compound-engineering workflow", () => {
     expect(getBuiltinWorkflow("builtin:coding")).toBeDefined();
     expect(getBuiltinWorkflow("builtin:compound-engineering")).toBeDefined();

packages/core/src/__tests__/workflow-ir-resolver.test.ts

@@ -89,6 +89,20 @@ describe("resolveWorkflowIrForTask", () => {
 });
 
 describe("resolveWorkflowIrById", () => {
+  it("resolves builtin:coding to the authored v2 IR with review column traits", async () => {
+    const store = makeStore({});
+    const ir = await resolveWorkflowIrById(store, "builtin:coding");
+
+    expect(ir.version).toBe("v2");
+    if (ir.version !== "v2") throw new Error("expected v2");
+    const inReview = ir.columns.find((column) => column.id === "in-review");
+    expect(inReview).toBeDefined();
+    expect(inReview!.traits.length).toBeGreaterThan(0);
+    expect(inReview!.traits).toEqual(
+      expect.arrayContaining([{ trait: "merge-blocker" }, { trait: "human-review" }]),
+    );
+  });
+
   it("parses a raw-string IR from the definition", async () => {
     const raw = JSON.stringify(CUSTOM_IR);
     const store = makeStore({ defs: { "wf-raw": { ir: raw } } });

packages/core/src/builtin-workflows.ts

@@ -1,3 +1,4 @@
+import { BUILTIN_CODING_WORKFLOW_IR } from "./builtin-coding-workflow-ir.js";
 import { BUILTIN_PR_WORKFLOW_IR } from "./builtin-pr-workflow-ir.js";
 import { BUILTIN_STEPWISE_CODING_WORKFLOW_IR } from "./builtin-stepwise-coding-workflow-ir.js";
 import { BUILTIN_WORKFLOW_SETTINGS } from "./builtin-workflow-settings.js";
@@ -84,16 +85,22 @@ function linear(spec: BuiltinSpec): WorkflowDefinition {
  * seams are honored only by the graph interpreter (flag on).
  */
 export const BUILTIN_WORKFLOWS: WorkflowDefinition[] = [
-  linear({
+  {
     id: "builtin:coding",
     name: "Coding (built-in)",
     description: "The standard coding pipeline: implement, review, then merge. Equivalent to the default behavior.",
-    nodes: [
-      { id: "execute", kind: "prompt", config: builtinPromptConfig("execute", "Execute") },
-      { id: "review", kind: "prompt", config: builtinPromptConfig("review", "Review") },
-      { id: "merge", kind: "prompt", config: builtinPromptConfig("merge", "Merge boundary") },
-    ],
-  }),
+    kind: "workflow",
+    ir: BUILTIN_CODING_WORKFLOW_IR,
+    layout: {
+      start: { x: 60, y: 160 },
+      execute: { x: 230, y: 160 },
+      review: { x: 400, y: 160 },
+      merge: { x: 570, y: 160 },
+      end: { x: 740, y: 160 },
+    },
+    createdAt: BUILTIN_TS,
+    updatedAt: BUILTIN_TS,
+  },
   linear({
     id: "builtin:quick-fix",
     name: "Quick fix (built-in)",

packages/dashboard/src/routes/__tests__/board-workflows-route.test.ts

@@ -112,7 +112,11 @@ describe("GET /tasks/board-workflows", () => {
     const body = res.body as {
       flagEnabled: boolean;
       defaultWorkflowId: string;
-      workflows: Array<{ id: string; name: string; columns: unknown[] }>;
+      workflows: Array<{
+        id: string;
+        name: string;
+        columns: Array<{ id: string; flags: { mergeBlocker?: boolean; humanReview?: boolean } }>;
+      }>;
       taskWorkflowIds: Record<string, string>;
     };
 
@@ -149,6 +153,9 @@ describe("GET /tasks/board-workflows", () => {
     const defaultLane = body.workflows.find((w) => w.id === DEFAULT_LANE);
     expect(Array.isArray(defaultLane?.columns)).toBe(true);
     expect((defaultLane?.columns.length ?? 0)).toBeGreaterThan(0);
+    const inReview = defaultLane?.columns.find((column) => column.id === "in-review");
+    expect(inReview?.flags.mergeBlocker).toBe(true);
+    expect(inReview?.flags.humanReview).toBe(true);
   });
 
   it("payload contract (flag ON): mixed default + custom ids → full taskWorkflowIds + deduped workflows", async () => {
@@ -173,7 +180,8 @@ describe("GET /tasks/board-workflows", () => {
     });
     const ids = payload.workflows.map((w) => w.id);
     expect(new Set(ids).size).toBe(ids.length); // deduped
-    expect(ids.sort()).toEqual([DEFAULT_LANE, custom.id].sort());
+    expect(ids).toContain(DEFAULT_LANE);
+    expect(ids).toContain(custom.id);
     const customLane = payload.workflows.find((w) => w.id === custom.id);
     expect(customLane?.name).toBe("Custom");
     expect((customLane?.columns.length ?? 0)).toBeGreaterThan(0);

packages/dashboard/src/routes/__tests__/board-workflows.test.ts

@@ -82,6 +82,10 @@ describe("buildBoardWorkflowsPayload", () => {
       "Done",
       "Archived",
     ]);
+    const inReview = defaultWf!.columns.find((c) => c.id === "in-review");
+    expect(inReview).toBeDefined();
+    expect(inReview!.flags.mergeBlocker).toBe(true);
+    expect(inReview!.flags.humanReview).toBe(true);
   });
 
   it("includes user-defined workflows even when no visible task references them", async () => {