fix(FN-branch-group): address fourth-round PR review feedback (#1357)

- needsPrRepair no longer short-circuited by the open-state guard: legacy
  fallback rows (finalized + prState open + prNumber null) now repair by
  creating the real PR on re-promotion; regression test added
- no-PR abandon route test asserts last persisted call + response body
- goal-provenance fallback test clears missionId on its own in-memory store
  so the feature-linkage path is genuinely exercised

packages/core/src/__tests__/mission-store.test.ts

@@ -2018,7 +2018,12 @@ describe("MissionStore", () => {
 
       const task = await ts.createTask({ title: "Task", description: "Linked task" });
       ms.linkFeatureToTask(feature.id, task.id);
-      db.prepare("UPDATE tasks SET missionId = NULL WHERE id = ?").run(task.id);
+      // Clear missionId on THIS test's in-memory TaskStore db (the outer `db`
+      // belongs to a different store) so the lookup genuinely exercises the
+      // feature-linkage fallback instead of the normal task→mission path.
+      (ts as unknown as { db: { prepare(sql: string): { run(...args: unknown[]): unknown } } }).db
+        .prepare("UPDATE tasks SET missionId = NULL WHERE id = ?")
+        .run(task.id);
 
       expect(ms.listGoalIdsForTask(task.id)).toEqual([goal.id]);
       expect(ms.listGoalsForTask(task.id)).toEqual([goal]);

packages/dashboard/src/__tests__/routes-branch-groups.test.ts

@@ -341,10 +341,11 @@ describe("branch group abandon (U6, R7)", () => {
     const res = await REQUEST(app, "POST", "/branch-groups/BG-AB/abandon", JSON.stringify({}), { "content-type": "application/json" });
     expect(res.status).toBe(200);
     expect(closeGroupPr).not.toHaveBeenCalled();
-    expect(updateBranchGroup).toHaveBeenCalledWith(
+    expect(updateBranchGroup).toHaveBeenLastCalledWith(
       "BG-AB",
       expect.objectContaining({ status: "abandoned", prState: "none" }),
     );
+    expect(res.body.group.prState).toBe("none");
   });
 });
 

packages/engine/src/__tests__/group-merge-coordinator.test.ts

@@ -866,6 +866,39 @@ describe("promoteBranchGroup finalized-but-PR-less repair (Fix #4 part 2)", () =
     expect(mainAfter).toBe(mainBefore);
   });
 
+  it("repairs the legacy fallback state: finalized + prState 'open' + prNumber null still creates the PR", async () => {
+    // The old code flipped prState to "open" without creating a PR — re-running
+    // with createGroupPr wired must not be short-circuited by the open-state guard.
+    const rootDir = makePrRepo();
+    let group = makeGroup({ status: "finalized", prState: "open", prNumber: null, prUrl: null });
+    let createCalls = 0;
+    const store = {
+      getBranchGroup: () => group,
+      getBranchGroupByBranchName: () => null,
+      listTasksByBranchGroup: async () => [landedMember("FN-A", group.branchName)],
+      updateBranchGroup: (_id: string, patch: Record<string, unknown>) => {
+        group = { ...group, ...patch };
+        return group;
+      },
+    } as any;
+
+    const result = await promoteBranchGroup({
+      rootDir,
+      groupId: group.id,
+      settings: prSettings,
+      store,
+      createGroupPr: async () => {
+        createCalls += 1;
+        return { prNumber: 91, prUrl: "https://github.com/x/y/pull/91", prState: "open" as const };
+      },
+    });
+
+    expect(result.reason).toBe("promoted");
+    expect(createCalls).toBe(1);
+    expect(group.prNumber).toBe(91);
+    expect(group.prState).toBe("open");
+  });
+
   it("a finalized group that already has a prNumber is still short-circuited (no repair, no PR re-create)", async () => {
     const rootDir = makePrRepo();
     let group = makeGroup({ status: "finalized", prState: "open", prNumber: 5, prUrl: "https://github.com/x/y/pull/5" });

packages/engine/src/group-merge-coordinator.ts

@@ -287,7 +287,10 @@ async function promoteBranchGroupInner(input: PromoteBranchGroupInput): Promise<
     };
   }
 
-  if (group.prState === "open") {
+  // Legacy fallback rows are exactly `finalized + prState:"open" + prNumber:null`
+  // (the old code flipped prState without creating a PR) — the repair path must
+  // not be short-circuited by the open-state guard for them.
+  if (!needsPrRepair && group.prState === "open") {
     return {
       groupId: group.id,
       promoted: false,