fix: Remove explicit port 443 from OAuth redirect URIs for Cloudflare compatibility

This fixes CORS errors when using Ajax requests after session timeout.
The issue was that redirect_uri included :443 port causing Cloudflare issues.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

src/BCards.Web/Program.cs

@@ -298,6 +298,16 @@ authBuilder.AddGoogle(options =>
 
     options.Events = new OAuthEvents
     {
+        OnRedirectToAuthorizationEndpoint = context =>
+        {
+            // Fix para Cloudflare - remover porta 443 explícita
+            if (!builder.Environment.IsDevelopment())
+            {
+                context.RedirectUri = context.RedirectUri.Replace(":443", "");
+            }
+            context.Response.Redirect(context.RedirectUri);
+            return Task.CompletedTask;
+        },
         OnRemoteFailure = context =>
         {
             var logger = context.HttpContext.RequestServices.GetRequiredService<ILogger<Program>>();