fix(workspace): remove false reattach banner, silence ai-merge ENOENT prune

- dashboard: remove the "Branch needs reattachment" banner. It fired for any
  in-review task with a null singular task.branch — the NORMAL state for a
  workspace task (attachment is per-sub-repo worktrees in workspaceWorktrees), so
  it was a permanent false positive. Genuine lost bindings are already reattached
  automatically by self-healing's reconcileInReviewBranchRebind (event-driven on
  move-to-in-review + sweep), so no manual user action is needed. Delete the
  now-obsolete rebind-banner test + its registry entry.
- engine/self-healing: reconcileInReviewBranchRebind now explicitly skips
  workspace tasks (never rebind candidates — their fusion/<id> branches live in
  the sub-repos, not the non-git browse root; null root branch is healthy).
- engine/merger-ai: pre-merge prune treats an absent ai-merge search root (ENOENT)
  as "nothing to prune" instead of warning on every workspace merge.
- test: add ToggleRight to the TaskDetailModal lucide mock (pre-existing gap from
  FN-6880 that broke the whole suite at import).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/dashboard/app/components/TaskDetailModal.tsx

@@ -24,8 +24,8 @@ import {
 } from "@fusion/core";
 import { isNearDuplicateCanonicalInactive } from "../../../core/src/near-duplicate-canonical";
 import { resolveEffectiveAutoMerge } from "../../../core/src/task-merge";
-import { uploadAttachment, deleteAttachment, updateTask, pauseTask, unpauseTask, fetchTaskDetail, fetchSettings, fetchGlobalSettings, requestSpecRevision, rebuildTaskSpec, approvePlan, rejectPlan, refineTask, fetchWorkflowResults, assignTask, fetchAgents, fetchAgent, recoverBranchBinding, refreshPrStatus, fetchBoardWorkflows, updateTaskCustomFields, summarizeTitle, api } from "../api";
-import type { RecoverBranchBindingOutcome, WorkflowFieldDefinition, CustomFieldRejection } from "../api";
+import { uploadAttachment, deleteAttachment, updateTask, pauseTask, unpauseTask, fetchTaskDetail, fetchSettings, fetchGlobalSettings, requestSpecRevision, rebuildTaskSpec, approvePlan, rejectPlan, refineTask, fetchWorkflowResults, assignTask, fetchAgents, fetchAgent, refreshPrStatus, fetchBoardWorkflows, updateTaskCustomFields, summarizeTitle, api } from "../api";
+import type { WorkflowFieldDefinition, CustomFieldRejection } from "../api";
 import { ApiRequestError } from "../api";
 import { TaskFieldsSection } from "./TaskFieldsSection";
 import type { ToastType } from "../hooks/useToast";
@@ -936,9 +936,7 @@ export function TaskDetailContent({
   const [githubTrackingEnabledDraft, setGithubTrackingEnabledDraft] = useState<boolean | null>(null);
   const [githubRepoOverrideError, setGithubRepoOverrideError] = useState<string | null>(null);
   const [isSavingGithubTracking, setIsSavingGithubTracking] = useState(false);
-  const [isRecoveringBranchBinding, setIsRecoveringBranchBinding] = useState(false);
   const [isCheckingPrStatus, setIsCheckingPrStatus] = useState(false);
-  const [recoverBranchBindingOutcome, setRecoverBranchBindingOutcome] = useState<RecoverBranchBindingOutcome | null>(null);
   const moveMenuRef = useRef<HTMLDivElement>(null);
   const activityListRef = useRef<HTMLDivElement>(null);
   const moveButtonRef = useRef<HTMLButtonElement>(null);
@@ -1045,8 +1043,6 @@ export function TaskDetailContent({
     setGithubTrackingEnabledDraft(null);
     setGithubRepoOverrideError(null);
     setIsEditing(false);
-    setRecoverBranchBindingOutcome(null);
-    setIsRecoveringBranchBinding(false);
   }, [task.id, task.title, task.description, task.branch, task.baseBranch, task.sourceIssue, task.executionMode, workingTask.githubTracking]);
 
   useEffect(() => {
@@ -2178,25 +2174,6 @@ export function TaskDetailContent({
   }, [onArchiveTask, confirm, task.id, nearDuplicateOf, addToast, requestClose]);
 
   const isTaskPaused = task.paused || task.userPaused;
-  const showRecoverBranchBindingBanner = task.column === "in-review" && !task.branch;
-
-  const handleRecoverBranchBinding = useCallback(async () => {
-    setIsRecoveringBranchBinding(true);
-    try {
-      const outcome = await recoverBranchBinding(task.id, projectId);
-      setRecoverBranchBindingOutcome(outcome);
-      if (outcome.result === "applied") {
-        addToast(t("taskDetail.branchBinding.reattached", "Reattached branch for {{id}} ({{branch}})", { id: task.id, branch: outcome.branch }), "success");
-        onTaskUpdated?.({ ...task, branch: outcome.branch, worktree: undefined });
-      } else {
-        addToast(t("taskDetail.branchBinding.skipped", "Branch reattachment skipped for {{id}}: {{reason}}", { id: task.id, reason: outcome.reason }), "info");
-      }
-    } catch (err) {
-      addToast(getErrorMessage(err), "error");
-    } finally {
-      setIsRecoveringBranchBinding(false);
-    }
-  }, [addToast, onTaskUpdated, projectId, task]);
 
   const handleTogglePause = useCallback(async () => {
     try {
@@ -4299,44 +4276,15 @@ export function TaskDetailContent({
             addToast={addToast}
           />
         )}
-        {showRecoverBranchBindingBanner && (
-          <div className="detail-section rebind-banner" role="status">
-            <div className="rebind-banner-header">
-              <GitBranch aria-hidden="true" />
-              <span className="rebind-banner-headline">{t("taskDetail.branchBinding.headline", "Branch needs reattachment")}</span>
-            </div>
-            <p className="rebind-banner-copy">
-              {t("taskDetail.branchBinding.copy", "This in-review task isn't currently attached to a fusion branch. If a live fusion branch still exists for it, you can reattach it here.")}
-            </p>
-            {recoverBranchBindingOutcome && (
-              <div className="rebind-banner-result">
-                {recoverBranchBindingOutcome.result === "applied"
-                  ? t("taskDetail.branchBinding.reattachedResult", "Reattached {{branch}} ({{count}} commits ahead of {{base}}).", { branch: recoverBranchBindingOutcome.branch, count: recoverBranchBindingOutcome.aheadCount, base: recoverBranchBindingOutcome.integrationBase })
-                  : t("taskDetail.branchBinding.skippedResult", "Reattachment skipped: {{reason}}", { reason: recoverBranchBindingOutcome.reason })}
-                {recoverBranchBindingOutcome.result === "skipped" && recoverBranchBindingOutcome.candidates?.length ? (
-                  <span>
-                    {` ${t("taskDetail.branchBinding.candidates", "Candidates:")} ${recoverBranchBindingOutcome.candidates.map((entry) => `${entry.branch} (${entry.aheadCount})`).join(", ")}`}
-                  </span>
-                ) : null}
-              </div>
-            )}
-            <div className="rebind-banner-actions">
-              <button
-                type="button"
-                className="btn btn-primary btn-sm"
-                onClick={() => void handleRecoverBranchBinding()}
-                disabled={isRecoveringBranchBinding}
-              >
-                {isRecoveringBranchBinding ? (
-                  <>
-                    <Loader2 size={16} className="spin" aria-hidden="true" />
-                    {t("taskDetail.branchBinding.reattaching", "Reattaching…")}
-                  </>
-                ) : t("taskDetail.branchBinding.reattachBtn", "Reattach branch")}
-              </button>
-            </div>
-          </div>
-        )}
+        {/*
+        FNXC:Workspace 2026-06-24-23:10:
+        The "Branch needs reattachment" banner was removed. It fired for any in-review task with a
+        null singular `task.branch`, which is the NORMAL, healthy state for a workspace task (its
+        attachment is the per-sub-repo worktrees in `task.workspaceWorktrees`, not a root branch), so
+        the banner was a permanent false positive for workspace tasks. Reattachment of a genuinely
+        lost binding is handled automatically by self-healing's reconcileInReviewBranchRebind, which
+        runs event-driven on the move-to-in-review and on its sweep — no manual user action needed.
+        */}
         <div className="modal-actions">
           {isEditing ? (
             <>

packages/dashboard/app/components/__tests__/TaskDetailModal.rebind-banner.test.tsx

@@ -1,110 +0,0 @@
-import { describe, it, expect, vi } from "vitest";
-import { render, screen } from "@testing-library/react";
-import userEvent from "@testing-library/user-event";
-import { TaskDetailModal } from "../TaskDetailModal";
-import * as api from "../../api";
-import { makeTask, noop, noopDelete, noopMerge, noopMove, noopOpenDetail, setupTaskDetailModalHooks } from "./TaskDetailModal.test-helpers";
-
-setupTaskDetailModalHooks();
-
-describe("TaskDetailModal rebind banner", () => {
-  it("shows banner only for in-review tasks with missing branch", () => {
-    const { rerender } = render(
-      <TaskDetailModal
-        task={makeTask({ column: "in-review", branch: null, worktree: "/tmp/wt" })}
-        onClose={noop}
-        onMoveTask={noopMove}
-        onDeleteTask={noopDelete}
-        onMergeTask={noopMerge}
-        onOpenDetail={noopOpenDetail}
-        addToast={noop}
-      />,
-    );
-
-    expect(screen.getByText("Branch needs reattachment")).toBeTruthy();
-
-    rerender(
-      <TaskDetailModal
-        task={makeTask({ column: "in-review", branch: "fusion/fn-099", worktree: null })}
-        onClose={noop}
-        onMoveTask={noopMove}
-        onDeleteTask={noopDelete}
-        onMergeTask={noopMerge}
-        onOpenDetail={noopOpenDetail}
-        addToast={noop}
-      />,
-    );
-    // FN-5113: branch present + worktree cleared is the healthy post-handoff/post-rebind state (see AGENTS.md FN-5083). Banner must NOT show.
-    expect(screen.queryByText("Branch needs reattachment")).toBeNull();
-
-    rerender(
-      <TaskDetailModal
-        task={makeTask({ column: "in-review", branch: "fusion/fn-099", worktree: "/tmp/wt" })}
-        onClose={noop}
-        onMoveTask={noopMove}
-        onDeleteTask={noopDelete}
-        onMergeTask={noopMerge}
-        onOpenDetail={noopOpenDetail}
-        addToast={noop}
-      />,
-    );
-    expect(screen.queryByText("Branch needs reattachment")).toBeNull();
-  });
-
-  it("calls recover endpoint and renders applied result", async () => {
-    const recoverSpy = vi.spyOn(api, "recoverBranchBinding").mockResolvedValueOnce({
-      taskId: "FN-099",
-      result: "applied",
-      branch: "fusion/fn-099",
-      aheadCount: 2,
-      integrationBase: "main",
-      previousBranch: null,
-    });
-
-    render(
-      <TaskDetailModal
-        task={makeTask({ column: "in-review", branch: null, worktree: null })}
-        onClose={noop}
-        onMoveTask={noopMove}
-        onDeleteTask={noopDelete}
-        onMergeTask={noopMerge}
-        onOpenDetail={noopOpenDetail}
-        addToast={noop}
-      />,
-    );
-
-    await userEvent.click(screen.getByRole("button", { name: "Reattach branch" }));
-
-    expect(recoverSpy).toHaveBeenCalledWith("FN-099", undefined);
-    expect(await screen.findByText(/Reattached fusion\/fn-099/)).toBeTruthy();
-  });
-
-  it("renders skipped reason and candidates", async () => {
-    vi.spyOn(api, "recoverBranchBinding").mockResolvedValueOnce({
-      taskId: "FN-099",
-      result: "skipped",
-      reason: "ambiguous-candidates",
-      candidates: [
-        { branch: "fusion/FN-099", aheadCount: 1 },
-        { branch: "fusion/fn-099", aheadCount: 2 },
-      ],
-    });
-
-    render(
-      <TaskDetailModal
-        task={makeTask({ column: "in-review", branch: null, worktree: null })}
-        onClose={noop}
-        onMoveTask={noopMove}
-        onDeleteTask={noopDelete}
-        onMergeTask={noopMerge}
-        onOpenDetail={noopOpenDetail}
-        addToast={noop}
-      />,
-    );
-
-    await userEvent.click(screen.getByRole("button", { name: "Reattach branch" }));
-
-    expect(await screen.findByText(/Reattachment skipped: ambiguous-candidates/)).toBeTruthy();
-    expect(screen.getByText(/fusion\/FN-099/)).toBeTruthy();
-  });
-});

packages/dashboard/app/components/__tests__/TaskDetailModal.test-helpers.ts

@@ -81,6 +81,10 @@ vi.mock("lucide-react", () => ({
   Split: () => null,
   Merge: () => null,
   Repeat: () => null,
+  // FNXC:Test 2026-06-24-23:30: WorkflowNodeEditor (lazy-loaded by TaskDetailModal) uses ToggleRight
+  // for the optional-group node (FN-6880); the explicit mock list omitted it, breaking every
+  // TaskDetailModal suite at import. Keep this list in sync with the node-editor icon set.
+  ToggleRight: () => null,
   ClipboardCheck: () => null,
   ListChecks: () => null,
   Code2: () => null,

packages/dashboard/vitest.config.ts

@@ -195,7 +195,6 @@ const qualityAppComponentTests = [
   "TaskDetailModal.create-pr-integration",
   "TaskDetailModal.github-tracking-header",
   "TaskDetailModal.github-tracking-stale",
-  "TaskDetailModal.rebind-banner",
   "TaskDocumentsTab",
   "TaskFieldsSection",
   "TaskForm",

packages/engine/src/merger-ai.ts

@@ -195,6 +195,16 @@ export async function pruneExistingAiMergeWorktrees(
     try {
       entries = readdirSync(tempRoot).filter((entry) => entry.startsWith(prefix));
     } catch (err: unknown) {
+      /*
+      FNXC:AiMerge 2026-06-24-23:10:
+      An absent ai-merge search root is the NORMAL case, not an error: the clean-room directory
+      (e.g. `<repo>/.fusion/ai-merge`) is created lazily only when an AI-merge worktree is made, so a
+      workspace sub-repo that has never been AI-merged has no such dir. ENOENT therefore means
+      "nothing to prune" — skip it silently rather than emitting an alarming warning on every merge.
+      Only non-ENOENT failures are surfaced, and only a non-ENOENT failure on the system tmpdir
+      (which always exists) remains fatal.
+      */
+      if ((err as NodeJS.ErrnoException)?.code === "ENOENT") continue;
       await log(`AI merge pre-merge prune: failed to read ${tempRoot}: ${getErrorMessage(err)}`);
       if (tempRoot === tmpdir()) throw err;
       continue;

packages/engine/src/self-healing.ts

@@ -575,7 +575,8 @@ type RebindOutcome =
       | "ambiguous-candidates"
       | "no-unique-work"
       | "unsafe-to-auto-mutate:user-paused"
-      | "unsafe-to-auto-mutate:checked-out";
+      | "unsafe-to-auto-mutate:checked-out"
+      | "workspace-task";
     candidates?: Array<{ branch: string; aheadCount: number }>;
   };
 
@@ -3884,6 +3885,21 @@ export class SelfHealingManager {
       for (const task of tasks) {
         if (options?.includeTaskIds && !options.includeTaskIds.has(task.id)) continue;
 
+        /*
+        FNXC:Workspace 2026-06-24-23:10:
+        A workspace task is NEVER a branch-rebind candidate. Its attachment is the per-sub-repo
+        worktrees in `task.workspaceWorktrees`, and its `fusion/<id>` branches live inside each
+        sub-repo — not in `this.options.rootDir`, which for a workspace is the non-git browse-only
+        root. A null `task.branch` is its HEALTHY steady state, so trying to rebind a root branch is
+        meaningless (every git probe below would fail-soft against the non-git root anyway). Skip it
+        explicitly. The slim list select now carries `workspaceWorktrees`, so `isWorkspaceTask` is
+        accurate on these slim rows.
+        */
+        if (isWorkspaceTask(task)) {
+          result.outcomes.push({ taskId: task.id, result: "skipped", reason: "workspace-task" });
+          continue;
+        }
+
         const existingBinding = task.branch;
         if (existingBinding) {
           try {