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.Web/Components/Routes.razor

@@ -0,0 +1,20 @@
+@using Microsoft.AspNetCore.Components.Authorization
+<CascadingAuthenticationState>
+    <Router AppAssembly="typeof(Program).Assembly">
+        <Found Context="routeData">
+            <AuthorizeRouteView RouteData="routeData" DefaultLayout="typeof(Layout.MainLayout)">
+                <NotAuthorized>
+                    @if (context.User.Identity?.IsAuthenticated != true)
+                    {
+                        <RedirectToLogin />
+                    }
+                    else
+                    {
+                        <p role="alert">You are not authorized to access this resource.</p>
+                    }
+                </NotAuthorized>
+            </AuthorizeRouteView>
+            <FocusOnNavigate RouteData="routeData" Selector="h1" />
+        </Found>
+    </Router>
+</CascadingAuthenticationState>