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/Runner/ContinueAsyncExceptionTests.cs

@@ -5,7 +5,6 @@ using ClaudeDo.Worker.Config;
 using ClaudeDo.Worker.Hub;
 using ClaudeDo.Worker.Runner;
 using ClaudeDo.Worker.Tests.Infrastructure;
-using ClaudeDo.Worker.Tests.Services;
 using Microsoft.Extensions.Logging.Abstractions;
 using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
 
@@ -33,7 +32,7 @@ public sealed class ContinueAsyncExceptionTests : IDisposable
     private TaskRunner BuildRunner(IClaudeProcess claude, ClaudeDoDbContext ctx)
     {
         var dbFactory = _db.CreateFactory();
-        var broadcaster = new HubBroadcaster(new FakeHubContext());
+        var broadcaster = new HubBroadcaster(new CapturingHubContext());
         var state = TaskStateServiceBuilder.Build(dbFactory).State;
         var wt = new WorktreeManager(new ClaudeDo.Data.Git.GitService(), dbFactory, _cfg, NullLogger<WorktreeManager>.Instance);
         return new TaskRunner(claude, dbFactory, broadcaster, wt, new ClaudeArgsBuilder(), _cfg,