feat(worker,ui): Online Inbox config + auth hub plumbing (Phase 2)

Hub: GetOnlineInboxState / SetOnlineInboxConfig / SetOnlineInboxAuth /
ClearOnlineInboxAuth. WorkerConfig.SaveOnlineInbox persists only the
online_inbox section. OnlineTokenStore + config registered always so hub
methods work when sync is disabled. IWorkerClient surface + all test fakes
synced. RedirectUri config (default http://localhost:8765/callback).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/ClaudeDo.Ui/Services/WorkerClient.cs

@@ -504,6 +504,18 @@ public partial class WorkerClient : ObservableObject, IAsyncDisposable, IWorkerC
         await _hub.InvokeAsync("QueuePlanningSubtasksAsync", parentTaskId, ct);
     }
 
+    public Task<OnlineInboxStateDto?> GetOnlineInboxStateAsync()
+        => TryInvokeAsync<OnlineInboxStateDto>("GetOnlineInboxState");
+
+    public async Task SetOnlineInboxConfigAsync(OnlineInboxConfigInputDto input)
+        => await _hub.InvokeAsync("SetOnlineInboxConfig", input);
+
+    public async Task SetOnlineInboxAuthAsync(string refreshToken)
+        => await _hub.InvokeAsync("SetOnlineInboxAuth", refreshToken);
+
+    public async Task ClearOnlineInboxAuthAsync()
+        => await _hub.InvokeAsync("ClearOnlineInboxAuth");
+
     // IWorkerClient explicit implementations (drop typed return values)
     async Task IWorkerClient.StartPlanningSessionAsync(string taskId, CancellationToken ct)
         => await StartPlanningSessionAsync(taskId, ct);
@@ -568,3 +580,21 @@ public sealed record WorktreeOverviewDto(
     bool PathExistsOnDisk);
 
 public sealed record ForceRemoveResultDto(bool Removed, string? Reason);
+
+public sealed record OnlineInboxStateDto(
+    bool Enabled,
+    string ApiBaseUrl,
+    string Authority,
+    string ClientId,
+    string Scopes,
+    string RedirectUri,
+    bool SignedIn);
+
+public sealed record OnlineInboxConfigInputDto(
+    bool Enabled,
+    string ApiBaseUrl,
+    int PollIntervalSeconds,
+    string Authority,
+    string ClientId,
+    string Scopes,
+    string RedirectUri);