feat(web): add real-time activity feed via SignalR

- Add ActivityHub and wire up SignalR in Program.cs
- Broadcast new context events from ContextController
- Connect SignalR client on Analytics page for live feed updates
- Restructure activity feed HTML to support live prepending
- Add slide-in animation for new activity items
- Update CORS to allow credentials for SignalR

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

TaskTracker.Api/Controllers/ContextController.cs

@@ -1,4 +1,6 @@
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.SignalR;
+using TaskTracker.Api.Hubs;
 using TaskTracker.Core.DTOs;
 using TaskTracker.Core.Entities;
 using TaskTracker.Core.Interfaces;
@@ -11,6 +13,7 @@ public class ContextController(
     IContextEventRepository contextRepo,
     IAppMappingRepository mappingRepo,
     ITaskRepository taskRepo,
+    IHubContext<ActivityHub> hubContext,
     ILogger<ContextController> logger) : ControllerBase
 {
     [HttpPost]
@@ -37,6 +40,17 @@ public class ContextController(
         }
 
         var created = await contextRepo.CreateAsync(contextEvent);
+
+        await hubContext.Clients.All.SendAsync("NewActivity", new
+        {
+            id = created.Id,
+            appName = created.AppName,
+            windowTitle = created.WindowTitle,
+            url = created.Url,
+            timestamp = created.Timestamp,
+            workTaskId = created.WorkTaskId
+        });
+
         return Ok(ApiResponse<ContextEvent>.Ok(created));
     }
 

TaskTracker.Api/Hubs/ActivityHub.cs

@@ -0,0 +1,5 @@
+using Microsoft.AspNetCore.SignalR;
+
+namespace TaskTracker.Api.Hubs;
+
+public class ActivityHub : Hub { }

TaskTracker.Api/Pages/Analytics.cshtml

@@ -87,13 +87,11 @@
     <section>
         <h2 class="section-title">Recent Activity</h2>
         <div class="surface">
+            <div id="activity-feed" class="activity-feed">
                 @if (Model.ActivityItems.Count == 0)
                 {
-                <div class="search-empty">No activity recorded in this time range.</div>
+                    <div class="search-empty" id="activity-empty">No activity recorded in this time range.</div>
                 }
-            else
-            {
-                <div id="activity-feed" class="activity-feed">
                 @foreach (var item in Model.ActivityItems)
                 {
                     <div class="activity-item">
@@ -116,7 +114,6 @@
                     Load more (@(Model.TotalActivityCount - Model.ActivityItems.Count) remaining)
                 </button>
             }
-            }
         </div>
     </section>
 </div>

TaskTracker.Api/Pages/Shared/_Layout.cshtml

@@ -78,6 +78,7 @@
     <script src="~/lib/htmx.min.js"></script>
     <script src="~/lib/Sortable.min.js"></script>
     <script src="~/lib/chart.umd.min.js"></script>
+    <script src="~/lib/signalr.min.js"></script>
     <script src="~/js/app.js"></script>
     @await RenderSectionAsync("Scripts", required: false)
 </body>

TaskTracker.Api/Program.cs

@@ -1,4 +1,5 @@
 using Microsoft.EntityFrameworkCore;
+using TaskTracker.Api.Hubs;
 using TaskTracker.Core.Interfaces;
 using TaskTracker.Infrastructure.Data;
 using TaskTracker.Infrastructure.Repositories;
@@ -31,12 +32,16 @@ builder.Services.AddCors(options =>
 {
     options.AddDefaultPolicy(policy =>
     {
-        policy.AllowAnyOrigin()
+        policy.SetIsOriginAllowed(_ => true)
               .AllowAnyHeader()
-              .AllowAnyMethod();
+              .AllowAnyMethod()
+              .AllowCredentials();
     });
 });
 
+// SignalR
+builder.Services.AddSignalR();
+
 // Razor Pages
 builder.Services.AddRazorPages();
 
@@ -57,5 +62,6 @@ app.UseCors();
 app.UseStaticFiles();
 app.MapRazorPages();
 app.MapControllers();
+app.MapHub<ActivityHub>("/hubs/activity");
 
 app.Run();

TaskTracker.Api/wwwroot/css/site.css

@@ -1281,6 +1281,21 @@ body::before {
     flex-shrink: 0;
 }
 
+@keyframes activity-slide-in {
+    from {
+        opacity: 0;
+        transform: translateY(-8px);
+    }
+    to {
+        opacity: 1;
+        transform: translateY(0);
+    }
+}
+
+.activity-item--new {
+    animation: activity-slide-in 0.3s ease-out;
+}
+
 
 /* ============================================================
    CHART CONTAINER

TaskTracker.Api/wwwroot/js/app.js

@@ -272,4 +272,60 @@
         }
     });
 
+    // ========================================
+    // SignalR — Real-time Activity Feed
+    // ========================================
+
+    function initActivityHub() {
+        var feed = document.getElementById('activity-feed');
+        if (!feed) return; // Not on the Analytics page
+
+        var connection = new signalR.HubConnectionBuilder()
+            .withUrl('/hubs/activity')
+            .withAutomaticReconnect()
+            .build();
+
+        connection.on('NewActivity', function(data) {
+            // Remove the empty-state placeholder if present
+            var empty = document.getElementById('activity-empty');
+            if (empty) empty.remove();
+
+            var item = document.createElement('div');
+            item.className = 'activity-item activity-item--new';
+
+            var displayText = data.url || data.windowTitle || '';
+            // Escape HTML to prevent XSS
+            var div = document.createElement('div');
+            div.textContent = data.appName || '';
+            var safeApp = div.innerHTML;
+            div.textContent = displayText;
+            var safeTitle = div.innerHTML;
+
+            item.innerHTML =
+                '<span class="activity-dot" style="background: var(--color-accent)"></span>' +
+                '<div class="activity-line"></div>' +
+                '<div class="activity-info">' +
+                    '<span class="activity-app">' + safeApp + '</span>' +
+                    '<span class="activity-title">' + safeTitle + '</span>' +
+                    '<span class="activity-time">just now</span>' +
+                '</div>';
+
+            feed.insertBefore(item, feed.firstChild);
+
+            // Cap visible items at 100 to prevent memory bloat
+            var items = feed.querySelectorAll('.activity-item');
+            if (items.length > 100) {
+                items[items.length - 1].remove();
+            }
+        });
+
+        connection.start().catch(function(err) {
+            console.error('SignalR connection error:', err);
+        });
+    }
+
+    document.addEventListener('DOMContentLoaded', function() {
+        initActivityHub();
+    });
+
 })();