feat(worker): map MCP HTTP endpoint and broadcast TaskUpdated

- Add PlanningMcpContextAccessor (Option A) to read PlanningMcpContext
  from HttpContext.Items set by PlanningTokenAuthMiddleware
- Annotate PlanningMcpService with [McpServerToolType]/[McpServerTool]
  and remove PlanningMcpContext ctx parameter from all tool methods
- Broadcast TaskUpdated(parentTaskId) via HubBroadcaster after every
  mutation in PlanningMcpService
- Refactor PlanningSessionManager to accept IDbContextFactory for
  singleton-safe use in DI; keep direct-repo ctor for tests
- Register PlanningSessionManager (singleton), IPlanningTerminalLauncher,
  PlanningMcpContextAccessor, PlanningMcpService, and MCP server in
  Program.cs; wire PlanningTokenAuthMiddleware and MapMcp("/mcp")
- Update PlanningMcpServiceTests with fake HttpContext accessor and
  no-op HubBroadcaster (avoids Moq dependency)

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

src/ClaudeDo.Worker/Program.cs

@@ -3,6 +3,7 @@ using ClaudeDo.Data.Git;
 using ClaudeDo.Data.Repositories;
 using ClaudeDo.Worker.Config;
 using ClaudeDo.Worker.Hub;
+using ClaudeDo.Worker.Planning;
 using ClaudeDo.Worker.Runner;
 using ClaudeDo.Worker.Services;
 using Microsoft.EntityFrameworkCore;
@@ -51,6 +52,22 @@ builder.Services.AddSingleton(sp => new DefaultAgentSeeder(
 builder.Services.AddSingleton<QueueService>();
 builder.Services.AddHostedService(sp => sp.GetRequiredService<QueueService>());
 
+// Planning session services.
+var planningSessionsDir = Path.Combine(
+    Environment.GetFolderPath(Environment.SpecialFolder.UserProfile),
+    ".todo-app", "planning-sessions");
+builder.Services.AddSingleton(sp =>
+    new PlanningSessionManager(
+        sp.GetRequiredService<IDbContextFactory<ClaudeDoDbContext>>(),
+        planningSessionsDir));
+builder.Services.AddSingleton<IPlanningTerminalLauncher, WindowsTerminalPlanningLauncher>();
+builder.Services.AddHttpContextAccessor();
+builder.Services.AddScoped<PlanningMcpContextAccessor>();
+builder.Services.AddScoped<PlanningMcpService>();
+builder.Services.AddMcpServer()
+    .WithHttpTransport()
+    .WithTools<PlanningMcpService>();
+
 // Loopback-only bind. Firewall is irrelevant for 127.0.0.1.
 builder.WebHost.UseUrls($"http://127.0.0.1:{cfg.SignalRPort}");
 
@@ -75,7 +92,9 @@ catch (Exception ex)
     app.Logger.LogWarning(ex, "Default agent seeding failed");
 }
 
+app.UseMiddleware<PlanningTokenAuthMiddleware>();
 app.MapHub<WorkerHub>("/hub");
+app.MapMcp("/mcp");
 
 app.Logger.LogInformation("ClaudeDo.Worker listening on http://127.0.0.1:{Port} (db: {Db})",
     cfg.SignalRPort, cfg.DbPath);