fix(list-sessions): clarify manager action button labels

The /listsessions buttons for owners/co-GMs only showed emoji + date,
so it was unclear what each button did. Add explicit verb labels:
- ❌ Отменить <date>
- ⏰ Перенести <date>
- ⬆️ С ожидания <date>
- 🗑 Удалить <date>

Update the renderer test to assert the new labels.

tests/GmRelay.Bot.Tests/Features/Sessions/ListSessions/SessionListMessageRendererTests.cs

@@ -32,6 +32,12 @@ public sealed class SessionListMessageRendererTests
         Assert.Contains(actions, a => a.Payload == $"reschedule_session:{sessionId}");
         Assert.Contains(actions, a => a.Payload == $"promote_waitlist:{sessionId}");
         Assert.Contains(actions, a => a.Payload == $"delete_session:{sessionId}");
+
+        var shortDate = new DateTime(2026, 5, 7, 16, 30, 0, DateTimeKind.Utc).FormatMoscowShort();
+        Assert.Contains(actions, a => a.Label == $"❌ Отменить {shortDate}");
+        Assert.Contains(actions, a => a.Label == $"⏰ Перенести {shortDate}");
+        Assert.Contains(actions, a => a.Label == $"⬆️ С ожидания {shortDate}");
+        Assert.Contains(actions, a => a.Label == $"🗑 Удалить {shortDate}");
     }
 
     [Fact]