feat: implement Blazor web interface for GM session management

- Created GmRelay.Web project (Blazor Server)
- Created GmRelay.Shared library for domain models and rendering
- Refactored GmRelay.Bot to use the Shared library
- Integrated Telegram Login widget with server-side HMAC verification
- Added Dashboard, Group Details, and Edit Session pages
- Enabled bot notifications and in-place message updates from web actions
- Updated .NET Aspire orchestration and Docker Compose configuration

src/GmRelay.Bot/Infrastructure/Scheduling/SessionSchedulerService.cs

@@ -1,5 +1,5 @@
 using Dapper;
-using GmRelay.Bot.Domain;
+using GmRelay.Shared.Domain;
 using GmRelay.Bot.Features.Confirmation.SendConfirmation;
 using GmRelay.Bot.Features.Reminders.SendJoinLink;
 using Npgsql;

src/GmRelay.Bot/Infrastructure/Telegram/UpdateRouter.cs

@@ -1,4 +1,6 @@
 // ... UpdateRouter will have CancelSessionHandler and cancel_session route instead of close_recruitment
+using GmRelay.Shared.Domain;
+using GmRelay.Shared.Rendering;
 using GmRelay.Bot.Features.Confirmation.HandleRsvp;
 using GmRelay.Bot.Features.Sessions.CreateSession;
 using GmRelay.Bot.Features.Sessions.ListSessions;
@@ -134,8 +136,8 @@ public sealed class UpdateRouter(
 
             var status = parts[1] switch
             {
-                "confirm" => Domain.RsvpStatus.Confirmed,
-                "decline" => Domain.RsvpStatus.Declined,
+                "confirm" => RsvpStatus.Confirmed,
+                "decline" => RsvpStatus.Declined,
                 _ => (string?)null
             };