Remove dotnet-ef tool config and IIS publish profiles

Deleted dotnet-tools.json (dotnet-ef config) and IIS publish profiles for .NET 7 and .NET 9 (IISProfileNet7Win64.pubxml, IISProfileNet9Win64.pubxml) to clean up unused deployment and tooling files.

EnvelopeGenerator.API/Models/ErrorViewModel.cs

@@ -0,0 +1,10 @@
+namespace EnvelopeGenerator.GeneratorAPI.Models;
+
+public class ErrorViewModel
+{
+    public string Title { get; init; } = "404";
+
+    public string Subtitle { get; init; } = "Hmmm...";
+
+    public string Body { get; init; } = "It looks like one of the developers fell asleep";
+}