feat(e2e): #148 /newsession scenario from creation to publication

- Add NewSessionScenario that walks the Telegram wizard:
  single game, title, skip description/cover, D&D 5e, 4h, datetime,
  capacity, online format, join link, public visibility, publish, confirm
- Add ClickInlineButtonAsync / ClickInlineButtonByTextAsync to TelegramUserClient
- Add local WizardCallback/Step constants mirroring GmRelay.Shared wizard wire format
- Program.cs now runs full flow: group setup + /newsession + cleanup

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/e2e/runner/WizardCallback.cs

@@ -0,0 +1,36 @@
+namespace GmRelay.E2E.Runner;
+
+/// <summary>
+/// Mirrors the wire format used by GmRelay.Shared.Features.Sessions.CreateSession.Wizard.WizardCallbackData.
+/// Kept local to avoid a project reference to GmRelay.Shared from the standalone E2E runner.
+/// </summary>
+public static class WizardCallback
+{
+    public const string Prefix = "wizard";
+
+    public static string Choice(string step, string choice) => $"{Prefix}:{step}:{choice}";
+
+    public static string Back() => $"{Prefix}:back";
+
+    public static string Cancel() => $"{Prefix}:cancel";
+
+    public static string Create() => $"{Prefix}:create";
+}
+
+public static class WizardStep
+{
+    public const string Type = "Type";
+    public const string Title = "Title";
+    public const string Description = "Description";
+    public const string Cover = "Cover";
+    public const string System = "System";
+    public const string Duration = "Duration";
+    public const string DateTime = "DateTime";
+    public const string Capacity = "Capacity";
+    public const string Format = "Format";
+    public const string Location = "Location";
+    public const string Visibility = "Visibility";
+    public const string PickClub = "PickClub";
+    public const string Publish = "Publish";
+    public const string Confirm = "Confirm";
+}