feat: ship agent progress visibility

backend/Controllers/DashboardController.cs

@@ -262,9 +262,9 @@ public class DashboardController(
     [HttpGet("tasks/{id:guid}")]
     public async Task<ActionResult<DashboardTaskDto>> GetTask(Guid id, CancellationToken ct)
     {
-        var task = await taskService.GetByIdAsync(id, ct);
+        var task = await taskService.GetDashboardTaskByIdAsync(id, ct);
         if (task is null) return NotFound(new { error = "Task not found." });
-        return Ok(MapToDto(task));
+        return Ok(task);
     }
 
     [HttpGet("tasks/{id:guid}/activity")]

backend/Models/Dashboard.cs

@@ -91,7 +91,9 @@ public sealed record DashboardTaskDto(
     DateTimeOffset CreatedAt,
     DateTimeOffset UpdatedAt,
     bool IsAgentTask = false,
-    string? ExpectedFrom = null
+    string? ExpectedFrom = null,
+    string? LastActivityMessage = null,
+    DateTimeOffset? LastActivityAt = null
 );
 
 public sealed record CreateDashboardTaskRequest(

backend/Repositories/ActivityRepository.cs

@@ -8,6 +8,18 @@ public sealed class ActivityRepository(NexusDbContext db) : IActivityRepository
     public Task<List<ActivityEvent>> GetRecentAsync(int take, CancellationToken ct = default)
         => db.Activity.AsNoTracking().OrderByDescending(x => x.CreatedAt).Take(take).ToListAsync(ct);
 
+    public Task<List<ActivityEvent>> GetRecentForTasksAsync(IEnumerable<Guid> taskIds, CancellationToken ct = default)
+    {
+        var ids = taskIds.Distinct().ToList();
+        if (ids.Count == 0)
+            return Task.FromResult(new List<ActivityEvent>());
+
+        return db.Activity.AsNoTracking()
+            .Where(x => x.TaskId.HasValue && ids.Contains(x.TaskId.Value))
+            .OrderByDescending(x => x.CreatedAt)
+            .ToListAsync(ct);
+    }
+
     public async Task<(List<ActivityEvent> Items, int TotalCount)> GetPagedAsync(
         string? type, string? sort, int page, int pageSize, CancellationToken ct = default)
     {

backend/Repositories/IActivityRepository.cs

@@ -5,6 +5,7 @@ namespace Nexus.Api.Repositories;
 public interface IActivityRepository
 {
     Task<List<ActivityEvent>> GetRecentAsync(int take, CancellationToken ct = default);
+    Task<List<ActivityEvent>> GetRecentForTasksAsync(IEnumerable<Guid> taskIds, CancellationToken ct = default);
     Task<(List<ActivityEvent> Items, int TotalCount)> GetPagedAsync(
         string? type, string? sort, int page, int pageSize, CancellationToken ct = default);
     Task<List<ActivityEvent>> GetByAgentAsync(string agentId, int take, CancellationToken ct = default);

backend/Services/ITaskService.cs

@@ -36,6 +36,7 @@ public interface ITaskService
     Task<int> ResetStaleInProgressTasksAsync(TimeSpan staleThreshold, CancellationToken ct = default);
     Task<IReadOnlyList<WorkTask>> GetChildTasksAsync(Guid parentId, CancellationToken ct = default);
     Task<List<ActivityEvent>> GetTaskActivityAsync(Guid taskId, CancellationToken ct = default);
+    Task<DashboardTaskDto?> GetDashboardTaskByIdAsync(Guid id, CancellationToken ct = default);
 
     // Agent Workflow Overview
     Task<IReadOnlyList<WorkTask>> GetWaitingTasksAsync(CancellationToken ct = default);

backend/Services/TaskService.cs

@@ -20,6 +20,15 @@ public sealed class TaskService(
     public async Task<WorkTask?> GetByIdAsync(Guid id, CancellationToken ct = default)
         => await taskRepo.GetByIdAsync(id, ct);
 
+    public async Task<DashboardTaskDto?> GetDashboardTaskByIdAsync(Guid id, CancellationToken ct = default)
+    {
+        var task = await taskRepo.GetByIdAsync(id, ct);
+        if (task is null) return null;
+
+        var activity = await activityRepo.GetRecentForTasksAsync([task.Id], ct);
+        return MapToDtoWithActivity(task, activity);
+    }
+
     public async Task<IReadOnlyList<WorkTask>> GetPendingApprovalAsync(CancellationToken ct = default)
         => await taskRepo.GetPendingApprovalAsync(ct);
 
@@ -162,35 +171,32 @@ public sealed class TaskService(
 
         var agentTasks = all.Where(t => t.IsAgentTask).ToList();
 
-        var waitingForBao = agentTasks
+        var activity = await activityRepo.GetRecentForTasksAsync(agentTasks.Select(t => t.Id), ct);
+
+        List<DashboardTaskDto> map(IEnumerable<WorkTask> tasks)
+            => tasks.Select(task => MapToDtoWithActivity(task, activity)).ToList();
+
+        var waitingForBao = map(agentTasks
             .Where(t => string.Equals(t.ExpectedFrom, "bao", StringComparison.OrdinalIgnoreCase) &&
-                        !string.Equals(t.State, "Done", StringComparison.OrdinalIgnoreCase))
-            .Select(MapToDto)
-            .ToList();
+                        !string.Equals(t.State, "Done", StringComparison.OrdinalIgnoreCase)));
 
-        var waitingForIris = agentTasks
+        var waitingForIris = map(agentTasks
             .Where(t => string.Equals(t.ExpectedFrom, "iris", StringComparison.OrdinalIgnoreCase) &&
-                        !string.Equals(t.State, "Done", StringComparison.OrdinalIgnoreCase))
-            .Select(MapToDto)
-            .ToList();
+                        !string.Equals(t.State, "Done", StringComparison.OrdinalIgnoreCase)));
 
-        var waitingForOthers = agentTasks
+        var waitingForOthers = map(agentTasks
             .Where(t =>
             {
                 var expected = (t.ExpectedFrom ?? "").ToLowerInvariant();
                 return expected != "bao" && expected != "iris" && !string.IsNullOrWhiteSpace(expected) &&
                        !string.Equals(t.State, "Done", StringComparison.OrdinalIgnoreCase);
-            })
-            .Select(MapToDto)
-            .ToList();
+            }));
 
-        var staleTasks = agentTasks
+        var staleTasks = map(agentTasks
             .Where(t =>
                 (string.Equals(t.State, "In progress", StringComparison.OrdinalIgnoreCase) ||
                  string.Equals(t.State, "Delegated", StringComparison.OrdinalIgnoreCase)) &&
-                t.UpdatedAt < threshold)
-            .Select(MapToDto)
-            .ToList();
+                t.UpdatedAt < threshold));
 
         return new AgentWorkflowOverview(waitingForBao, waitingForIris, waitingForOthers,
             staleTasks, staleThreshold);
@@ -533,6 +539,21 @@ public sealed class TaskService(
         t.ParentTaskId, t.DueDate, t.CreatedAt, t.UpdatedAt,
         t.IsAgentTask, t.ExpectedFrom);
 
+    private static DashboardTaskDto MapToDtoWithActivity(WorkTask t, IEnumerable<ActivityEvent> activity)
+    {
+        var last = activity
+            .Where(e => e.TaskId == t.Id)
+            .OrderByDescending(e => e.CreatedAt)
+            .FirstOrDefault();
+
+        return new DashboardTaskDto(
+            t.Id, t.Title, t.Detail, t.Source, t.State, t.Priority, t.AssignedTo,
+            t.ParentTaskId, t.DueDate, t.CreatedAt, t.UpdatedAt,
+            t.IsAgentTask, t.ExpectedFrom,
+            last?.Message,
+            last?.CreatedAt);
+    }
+
     /// <summary>
     /// Validates AssignedTo — only recognized agent values are accepted.
     /// Returns null for invalid values.