feat(FN-4091): fix stale blocker in WorkflowResultsTab

The branch delivers a fix for stale blockers in the WorkflowResultsTab component, with the primary logic change in the component file and comprehensive test coverage added in the companion test suite.

Fusion-Task-Id: FN-4091

packages/core/src/__tests__/task-merge.test.ts

@@ -305,11 +305,38 @@ describe("getTaskCompletionBlocker", () => {
     await expect(getTaskCompletionBlocker(baseCompletionTask)).resolves.toBeUndefined();
   });
 
-  it("returns a reason when task has blockedBy", async () => {
+  it("returns a reason when task has blockedBy without resolveTask", async () => {
     await expect(getTaskCompletionBlocker({ ...baseCompletionTask, blockedBy: "FN-123" }))
       .resolves.toBe("task is blocked by FN-123");
   });
 
+  it("ignores blockedBy when resolveTask reports the blocker missing", async () => {
+    const resolveTask = async () => null;
+
+    await expect(getTaskCompletionBlocker({
+      ...baseCompletionTask,
+      blockedBy: "FN-4054",
+    }, { resolveTask })).resolves.toBeUndefined();
+  });
+
+  it.each(["done", "archived"] as const)("ignores blockedBy when resolveTask reports the blocker is %s", async (column) => {
+    const resolveTask = async () => ({ id: "FN-4054", column });
+
+    await expect(getTaskCompletionBlocker({
+      ...baseCompletionTask,
+      blockedBy: "FN-4054",
+    }, { resolveTask })).resolves.toBeUndefined();
+  });
+
+  it.each(["todo", "in-progress", "in-review"] as const)("returns a reason when resolveTask reports an active blocker in %s", async (column) => {
+    const resolveTask = async () => ({ id: "FN-123", column });
+
+    await expect(getTaskCompletionBlocker({
+      ...baseCompletionTask,
+      blockedBy: "FN-123",
+    }, { resolveTask })).resolves.toBe("task is blocked by FN-123");
+  });
+
   it("returns a reason when a dependency is unresolved", async () => {
     const resolveTask = async (taskId: string) => {
       if (taskId === "FN-001") {

packages/core/src/task-merge.ts

@@ -123,6 +123,11 @@ export function isTaskReadyForMerge(
 }
 
 export interface TaskCompletionBlockerOptions {
+  /**
+   * Resolves a task reference so completion gating can distinguish live blockers
+   * from stale `blockedBy` markers. Missing tasks and blockers already in
+   * `done`/`archived` are treated as non-blocking.
+   */
   resolveTask?: (taskId: string) => Promise<Pick<Task, "id" | "column"> | null | undefined>;
 }
 
@@ -138,8 +143,16 @@ export async function getTaskCompletionBlocker(
   task: Pick<Task, "blockedBy" | "dependencies">,
   options: TaskCompletionBlockerOptions = {},
 ): Promise<string | undefined> {
-  if (task.blockedBy?.trim()) {
-    return `task is blocked by ${task.blockedBy.trim()}`;
+  const blockedBy = task.blockedBy?.trim();
+  if (blockedBy) {
+    if (!options.resolveTask) {
+      return `task is blocked by ${blockedBy}`;
+    }
+
+    const blocker = await options.resolveTask(blockedBy);
+    if (blocker && blocker.column !== "done" && blocker.column !== "archived") {
+      return `task is blocked by ${blockedBy}`;
+    }
   }
 
   const dependencies = task.dependencies ?? [];