fix(FN-820): fix activity log data source selection in project view

- Fix ActivityLogModal to correctly select between project and central activity logs based on project context
- Add regression tests verifying data source selection logic for single-project and multi-project scenarios
- Update README documentation with activity log data source rules and selection behavior

packages/dashboard/README.md

@@ -224,8 +224,8 @@ Browse and edit task worktree files directly from the task detail modal:
 View a centralized timeline of all task lifecycle events. Click the history icon in the header to open the Activity Log modal.
 
 **Data Source**:
-- **Single-project mode** (default): Reads from the per-project activity log via `/api/activity`, which is always populated with task lifecycle events for the current project.
-- **Multi-project mode**: When projects are registered, the modal reads from the unified central feed via `/api/activity-feed`, which aggregates activity across all registered projects. A project filter dropdown allows narrowing results to a specific project.
+- **Project view** (when a project is selected): Reads from the per-project activity log via `/api/activity`, which is always populated with task lifecycle events for the current project. This ensures reliable activity visibility in normal dashboard use.
+- **Overview mode** (no project selected): Reads from the unified central feed via `/api/activity-feed`, which aggregates activity across all registered projects. The project filter dropdown allows narrowing results to a specific project.
 
 **Features**:
 - **Event Types**: Track task:created, task:moved, task:merged, task:failed, task:deleted, and settings:updated events

packages/dashboard/app/App.tsx

@@ -732,6 +732,7 @@ function AppInner() {
         tasks={tasks}
         projectId={currentProject?.id}
         projects={projects}
+        currentProject={currentProject}
         onOpenTaskDetail={(taskId) => {
           const task = tasks.find((t) => t.id === taskId);
           if (task) {

packages/dashboard/app/components/ActivityLogModal.tsx

@@ -15,6 +15,8 @@ interface ActivityLogModalProps {
   projects?: ProjectInfo[];
   /** Called when project filter changes */
   onProjectFilterChange?: (projectId: string | undefined) => void;
+  /** Current project context - when set, uses per-project activity log */
+  currentProject?: ProjectInfo | null;
 }
 
 const EVENT_TYPE_LABELS: Record<ActivityEventType, string> = {
@@ -57,10 +59,11 @@ function formatTimestamp(timestamp: string): string {
  * ActivityLogModal - Activity log with project attribution and filtering
  *
  * Data source selection:
- * - Single-project mode (no projects list): reads from the per-project activity
+ * - Project view (currentProject set): reads from the per-project activity
  *   log via /api/activity, which is always populated with task lifecycle events.
- * - Multi-project mode (projects list provided): reads from the unified central
+ * - Overview mode (no currentProject): reads from the unified central
  *   feed via /api/activity-feed, which aggregates activity across all projects.
+ *   The project filter dropdown allows narrowing results to a specific project.
  *
  * Features:
  * - Project name badge for each activity entry
@@ -76,6 +79,7 @@ export function ActivityLogModal({
   projectId,
   projects = [],
   onProjectFilterChange,
+  currentProject,
 }: ActivityLogModalProps) {
   const [filteredType, setFilteredType] = useState<ActivityEventType | "all">("all");
   const [filteredProjectId, setFilteredProjectId] = useState<string | "all">(projectId || "all");
@@ -90,10 +94,14 @@ export function ActivityLogModal({
   const activityType = filteredType === "all" ? undefined : filteredType;
   const activeProjectId = filteredProjectId === "all" ? undefined : filteredProjectId;
   
-  // Determine data source: use unified central feed only when projects list
-  // is provided (multi-project context). In single-project mode the hook reads
-  // from the per-project activity log which is always populated.
-  const useCentralFeed = projects.length > 0;
+  // Determine data source:
+  // - In project view (currentProject set): use per-project activity log (/api/activity)
+  //   which is always populated with task lifecycle events for the current project.
+  // - In overview mode (no currentProject): use unified central feed (/api/activity-feed)
+  //   which aggregates activity across all registered projects.
+  // The project filter dropdown (projects prop) still appears to filter by project,
+  // but the default data source is the per-project log in project view.
+  const useCentralFeed = !currentProject && projects.length > 0;
 
   // Use the hook for data fetching
   const { 

packages/dashboard/app/components/__tests__/ActivityLogModal.test.tsx

@@ -145,7 +145,7 @@ describe("ActivityLogModal", () => {
     });
   });
 
-  it("calls unified feed API when projects are provided (multi-project mode)", async () => {
+  it("calls unified feed API when projects are provided but no currentProject (overview mode)", async () => {
     const mockProjects = [
       { id: "proj_1", name: "Project One", path: "/path/1", status: "active" as const, isolationMode: "in-process" as const, createdAt: "", updatedAt: "" },
     ];
@@ -161,11 +161,102 @@ describe("ActivityLogModal", () => {
     );
 
     await waitFor(() => {
-      // Multi-project mode: uses fetchActivityFeed (not fetchActivityLog)
+      // Overview mode (no currentProject): uses fetchActivityFeed
       expect(mockFetchActivityFeed).toHaveBeenCalled();
     });
   });
 
+  // ── Regression Tests for FN-820 ────────────────────────────────────
+  // The bug was that the modal used the unified central feed whenever projects
+  // existed, even in normal project view where per-project activity log should be used.
+
+  it("uses per-project log when currentProject is set even with multiple projects registered", async () => {
+    const mockProjects = [
+      { id: "proj_1", name: "Project One", path: "/path/1", status: "active" as const, isolationMode: "in-process" as const, createdAt: "", updatedAt: "" },
+      { id: "proj_2", name: "Project Two", path: "/path/2", status: "active" as const, isolationMode: "in-process" as const, createdAt: "", updatedAt: "" },
+    ];
+    const mockCurrentProject = { id: "proj_1", name: "Project One", path: "/path/1", status: "active" as const, isolationMode: "in-process" as const, createdAt: "", updatedAt: "" };
+
+    render(
+      <ActivityLogModal
+        isOpen={true}
+        onClose={mockOnClose}
+        tasks={mockTasks}
+        projects={mockProjects}
+        currentProject={mockCurrentProject}
+        onOpenTaskDetail={mockOnOpenTaskDetail}
+      />
+    );
+
+    await waitFor(() => {
+      // Project view (currentProject set): uses per-project log even with multiple projects
+      expect(mockFetchActivityLog).toHaveBeenCalled();
+      expect(mockFetchActivityFeed).not.toHaveBeenCalled();
+    });
+  });
+
+  it("uses per-project log when currentProject is set and projects list is empty", async () => {
+    const mockCurrentProject = { id: "proj_1", name: "Project One", path: "/path/1", status: "active" as const, isolationMode: "in-process" as const, createdAt: "", updatedAt: "" };
+
+    render(
+      <ActivityLogModal
+        isOpen={true}
+        onClose={mockOnClose}
+        tasks={mockTasks}
+        currentProject={mockCurrentProject}
+        onOpenTaskDetail={mockOnOpenTaskDetail}
+      />
+    );
+
+    await waitFor(() => {
+      // Project view: uses per-project log
+      expect(mockFetchActivityLog).toHaveBeenCalled();
+      expect(mockFetchActivityFeed).not.toHaveBeenCalled();
+    });
+  });
+
+  it("uses unified feed in overview mode with multiple projects but no currentProject", async () => {
+    const mockProjects = [
+      { id: "proj_1", name: "Project One", path: "/path/1", status: "active" as const, isolationMode: "in-process" as const, createdAt: "", updatedAt: "" },
+      { id: "proj_2", name: "Project Two", path: "/path/2", status: "active" as const, isolationMode: "in-process" as const, createdAt: "", updatedAt: "" },
+    ];
+
+    render(
+      <ActivityLogModal
+        isOpen={true}
+        onClose={mockOnClose}
+        tasks={mockTasks}
+        projects={mockProjects}
+        // No currentProject - overview mode
+        onOpenTaskDetail={mockOnOpenTaskDetail}
+      />
+    );
+
+    await waitFor(() => {
+      // Overview mode: uses unified feed
+      expect(mockFetchActivityFeed).toHaveBeenCalled();
+      expect(mockFetchActivityLog).not.toHaveBeenCalled();
+    });
+  });
+
+  it("uses per-project log by default when only projectId is passed (backward compatible)", async () => {
+    render(
+      <ActivityLogModal
+        isOpen={true}
+        onClose={mockOnClose}
+        tasks={mockTasks}
+        projectId="proj_1"
+        onOpenTaskDetail={mockOnOpenTaskDetail}
+      />
+    );
+
+    await waitFor(() => {
+      // Default behavior without projects: uses per-project log
+      expect(mockFetchActivityLog).toHaveBeenCalled();
+      expect(mockFetchActivityFeed).not.toHaveBeenCalled();
+    });
+  });
+
   it("filters by type when dropdown changed", async () => {
     render(
       <ActivityLogModal