test(worker): consolidate fakes into Infrastructure/, drop tag-era names

- Extract FakeClaudeProcess to Infrastructure/FakeClaudeProcess.cs (was
  defined inline in QueueServiceTests #region); all consumers updated
- Replace duplicate FakeHubContext/FakeHubClients/FakeClientProxy
  (QueueServiceTests) with existing CapturingHubContext from Infrastructure
  across all 7 affected files; Planning's file-local FakeHubContext kept
- Rename SeedListWithAgentTag → SeedListAsync (return Task<string>, drop
  unused agentTagId tuple element) and SeedListWithAgentTagAsync → SeedListAsync
- PrimeRunnerTests keeps its private nested FakeClaudeProcess: constructor
  API (delay/exitCode/lines/result params) differs from the shared one and
  replacement would require rewriting every test in that file

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

tests/ClaudeDo.Worker.Tests/Services/QueueServiceSlotGuardTests.cs

@@ -6,7 +6,6 @@ using ClaudeDo.Worker.Hub;
 using ClaudeDo.Worker.Queue;
 using ClaudeDo.Worker.Runner;
 using ClaudeDo.Worker.Tests.Infrastructure;
-using Microsoft.AspNetCore.SignalR;
 using Microsoft.Extensions.Logging.Abstractions;
 using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
 
@@ -49,7 +48,7 @@ public sealed class QueueServiceSlotGuardTests : IDisposable
         Func<string, string, IReadOnlyList<string>, Func<string, Task>, CancellationToken, Task<RunResult>>? handler = null)
     {
         var fake = new FakeClaudeProcess(handler);
-        var broadcaster = new HubBroadcaster(new FakeHubContext());
+        var broadcaster = new HubBroadcaster(new CapturingHubContext());
         var dbFactory = _db.CreateFactory();
         var wtManager = new WorktreeManager(new ClaudeDo.Data.Git.GitService(), dbFactory, _cfg, NullLogger<WorktreeManager>.Instance);
         var argsBuilder = new ClaudeArgsBuilder();
@@ -63,7 +62,7 @@ public sealed class QueueServiceSlotGuardTests : IDisposable
         return (service, fake);
     }
 
-    private async Task<string> SeedListWithAgentTagAsync()
+    private async Task<string> SeedListAsync()
     {
         var listId = Guid.NewGuid().ToString();
         await _listRepo.AddAsync(new ListEntity { Id = listId, Name = "Test", CreatedAt = DateTime.UtcNow });
@@ -88,7 +87,7 @@ public sealed class QueueServiceSlotGuardTests : IDisposable
     [Fact]
     public async Task RunNow_Throws_When_Task_Already_Running_In_Queue_Slot()
     {
-        var listId = await SeedListWithAgentTagAsync();
+        var listId = await SeedListAsync();
         var task = await SeedQueuedTaskAsync(listId);
 
         // Gate keeps the queue slot occupied indefinitely.
@@ -119,7 +118,7 @@ public sealed class QueueServiceSlotGuardTests : IDisposable
     [Fact]
     public async Task ContinueTask_Throws_When_Task_Already_Running_In_Queue_Slot()
     {
-        var listId = await SeedListWithAgentTagAsync();
+        var listId = await SeedListAsync();
         var task = await SeedQueuedTaskAsync(listId);
 
         var tcs = new TaskCompletionSource<RunResult>();