FN-7935: route mailbox artifact View task to the popped-out task-detail window

Mailbox artifact "View task" now opens the producing task in the same shared, movable/resizable floating task-detail window used elsewhere in the dashboard, instead of the docked task-detail modal.

- MainContent's MailboxView onOpenTask handler now calls popOutTaskDetail(task) after fetchTaskDetail resolves, instead of openDetailTask(task), matching DocumentsView's artifact-task open path
- add regression test verifying mailbox artifact "View task" clicks resolve the task and route to popOutTaskDetail (not openDetailTask)
- update docs/dashboard-guide.md to describe the shared movable/resizable task-detail window behavior
- add changeset (patch) documenting the fix for @runfusion/fusion

Files changed:
 .changeset/fn-7935-mailbox-artifact-view-task-popout.md                        |  7 ++
 docs/dashboard-guide.md                                                        |  2 +-
 packages/dashboard/app/components/dashboard/MainContent.tsx                    |  8 ++-
 .../MainContent.mailbox-view-task.test.tsx                                     | 83 ++++++++++++++++++++++
 4 files changed, 97 insertions(+), 3 deletions(-)

Fusion-Task-Id: FN-7935

Fusion-Task-Lineage: 51374962-aa36-4390-a6b5-b519e7fc2bf2

Co-authored-by: Fusion (runfusion.ai) <noreply@runfusion.ai>

.changeset/fn-7935-mailbox-artifact-view-task-popout.md

@@ -0,0 +1,7 @@
+---
+"@runfusion/fusion": patch
+---
+
+summary: Mailbox artifact "View task" now opens the same movable, resizable task window used elsewhere.
+category: fix
+dev: MainContent mailbox onOpenTask routes fetchTaskDetail -> popOutTaskDetail (floating-window--task-detail) instead of the docked openDetailTask modal, matching DocumentsView's artifact-task path.

docs/dashboard-guide.md

@@ -632,7 +632,7 @@ Mailbox view shows inbox/outbox communication threads and unread state.
 - Inbox renders one row per message (no sender-based collapsing)
 - clicking a message in the Mail tab opens the task detail pane with full message content and conversation context
 - reply rows in the mailbox modal can expand inline to show the replied-to message context for easier thread reading
-- when an agent or dashboard chat session registers an artifact with `fn_artifact_register`, Fusion sends a best-effort `system` → user inbox message announcing the new artifact (for example, `New image artifact registered: <title>`) with metadata for `artifactId`, `artifactType`, `title`, optional `mimeType`, `authorId`, and optional `taskId`; notification delivery is informational and never blocks or rolls back the artifact registration. Artifact notifications are actionable in message detail views: image artifacts show an inline preview plus **Open artifact**, while video/audio/document/other artifacts show an **Open artifact** link to the managed media URL. When `taskId` metadata is present, the same artifact block also shows **View task** so users can open the producing task detail directly from the mailbox.
+- when an agent or dashboard chat session registers an artifact with `fn_artifact_register`, Fusion sends a best-effort `system` → user inbox message announcing the new artifact (for example, `New image artifact registered: <title>`) with metadata for `artifactId`, `artifactType`, `title`, optional `mimeType`, `authorId`, and optional `taskId`; notification delivery is informational and never blocks or rolls back the artifact registration. Artifact notifications are actionable in message detail views: image artifacts show an inline preview plus **Open artifact**, while video/audio/document/other artifacts show an **Open artifact** link to the managed media URL. When `taskId` metadata is present, the same artifact block also shows **View task** so users can open the producing task detail directly from the mailbox in the shared movable/resizable task-detail window.
 - on first engine startup under Fusion `0.59.x`, each project receives one best-effort `system` inbox notice about the upcoming embedded-Postgres storage migration with the Discord help link; `metadata.kind = "postgres-migration-notice"` prevents duplicates across restarts.
 - mailbox now includes an **Approvals** tab with pending and history filters (`approved` / `denied` / `completed`), approval detail context, and inline approve/deny actions for pending requests
 - for approvals gated by an agent's permission policy (permanent agents and task-worker heartbeats), the Approvals detail pane renders the gated action's real payload — tool name, shell command line or structured arguments, and working directory when present — instead of only a generic "Agent gated action for `<tool>`" summary; a stateless heartbeat retrying the same gated command reuses the existing pending approval instead of creating a duplicate (FN-7609)

packages/dashboard/app/components/dashboard/MainContent.tsx

@@ -358,10 +358,14 @@ export function MainContent({
         <MailboxView
           projectId={currentProject?.id}
           addToast={addToast}
-          /* FNXC:ArtifactRegistry 2026-07-12-00:00: Artifact-registration mail notifications open their producing task through the shared task-detail fetch path so the mailbox does not invent a separate deep-link scheme. */
+          /*
+          FNXC:ArtifactRegistry 2026-07-12-00:00: Artifact-registration mail notifications open their producing task through the shared task-detail fetch path so the mailbox does not invent a separate deep-link scheme.
+
+          FNXC:ArtifactRegistry 2026-07-13-00:00: Mailbox artifact "View task" opens the producing task in the shared movable/resizable popped-out task-detail FloatingWindow (`popOutTaskDetail`), matching DocumentsView's artifact-task path instead of the docked `openDetailTask` modal, so the modal has full resize/move parity.
+          */
           onOpenTask={(taskId) => {
             void fetchTaskDetail(taskId, currentProject?.id)
-              .then((task) => openDetailTask(task as TaskDetail))
+              .then((task) => popOutTaskDetail(task))
               .catch(() => addToast?.("Failed to open task", "error"));
           }}
           onUnreadCountChange={setMailboxUnreadCount}

packages/dashboard/app/components/dashboard/__tests__/MainContent.mailbox-view-task.test.tsx

@@ -0,0 +1,83 @@
+import { render, screen, waitFor } from "@testing-library/react";
+import { describe, expect, it, vi } from "vitest";
+import type { TaskDetail } from "@fusion/core";
+import { MainContent } from "../MainContent";
+import type { MainContentProps } from "../types";
+
+const { fetchTaskDetailMock } = vi.hoisted(() => ({
+  fetchTaskDetailMock: vi.fn(),
+}));
+
+vi.mock("../../../api", () => ({
+  fetchTaskDetail: fetchTaskDetailMock,
+}));
+
+vi.mock("../../MailboxView", () => ({
+  MailboxView: ({ onOpenTask }: { onOpenTask?: (taskId: string) => void }) => (
+    <button type="button" onClick={() => onOpenTask?.("FN-7935")}>Open mailbox artifact task</button>
+  ),
+}));
+
+function mainContentProps(overrides: Partial<MainContentProps> = {}): MainContentProps {
+  return {
+    showBackendConnectionErrorPage: false,
+    projectsError: null,
+    t: ((key: string, fallback?: string) => fallback ?? key) as MainContentProps["t"],
+    retryingProjects: false,
+    handleRetryProjects: vi.fn(),
+    shellApi: null,
+    taskView: "mailbox",
+    modalManager: {} as MainContentProps["modalManager"],
+    handleChangeTaskView: vi.fn(),
+    refreshAppSettings: vi.fn(async () => undefined),
+    addToast: vi.fn(),
+    currentProject: { id: "project-1", name: "Project 1" } as MainContentProps["currentProject"],
+    viewMode: "project",
+    tasks: [],
+    workflowSteps: [],
+    openDetailTask: vi.fn(),
+    popOutTaskDetail: vi.fn(),
+    setMailboxUnreadCount: vi.fn(),
+    settingsLoaded: true,
+    skillsEnabled: true,
+    insightsEnabled: true,
+    researchEnabled: true,
+    evalsEnabled: true,
+    memoryEnabled: true,
+    goalsEnabled: true,
+    todosEnabled: true,
+    nodesEnabled: true,
+    capacityRiskBannerEnabled: false,
+    capacityRiskDismissed: false,
+    capacityRiskSignal: { level: "low", reasons: [] } as unknown as MainContentProps["capacityRiskSignal"],
+    ...overrides,
+  } as unknown as MainContentProps;
+}
+
+describe("MainContent mailbox artifact View task routing", () => {
+  it("opens mailbox artifact tasks in the shared popped-out task-detail window", async () => {
+    const fetchedTask = {
+      id: "FN-7935",
+      title: "Mailbox artifact task",
+      description: "Task opened from a mailbox artifact message",
+      column: "todo",
+      status: "todo",
+      dependencies: [],
+      createdAt: new Date(0).toISOString(),
+      updatedAt: new Date(0).toISOString(),
+      steps: [],
+    } as unknown as TaskDetail;
+    const openDetailTask = vi.fn();
+    const popOutTaskDetail = vi.fn();
+
+    fetchTaskDetailMock.mockResolvedValueOnce(fetchedTask);
+
+    render(<MainContent {...mainContentProps({ openDetailTask, popOutTaskDetail })} />);
+
+    screen.getByText("Open mailbox artifact task").click();
+
+    await waitFor(() => expect(popOutTaskDetail).toHaveBeenCalledWith(fetchedTask));
+    expect(fetchTaskDetailMock).toHaveBeenCalledWith("FN-7935", "project-1");
+    expect(openDetailTask).not.toHaveBeenCalled();
+  });
+});