Gum Source-Linked Project

For manually running a MonoGameGum/GumCommon change in a real game (see the tdd skill for when a unit test isn't enough). Two of Gum's own samples are already working reference projects for this exact pattern — start from one of them rather than guessing:

• Code-only (no .gumx, UI built via C#): Samples/MonoGameGumInCode/MonoGameGumInCode/MonoGameGumInCode.csproj
• File-based (loads a real .gumx from Content/): Samples/GumFormsSample/MonoGameGumFormsSample/MonoGameGumFormsSample.csproj

Fastest path: dotnet new mgdesktopgl, then rewire

1. dotnet new install MonoGame.Templates.CSharp — not bundled with the SDK.
2. dotnet new mgdesktopgl -o <dir> -n <ProjectName>.
3. In the generated .csproj: set <TargetFramework>net8.0</TargetFramework> (the template defaults to the newest installed SDK, which can be ahead of Gum's net8.0) and pin MonoGame.Framework.DesktopGL/MonoGame.Content.Builder.Task to 3.8.4.1 — the exact version every Gum sample uses — instead of the template's floating 3.8.*.
4. Add <ProjectReference Include="..\..\Gum\MonoGameGum\MonoGameGum.csproj" /> (path relative to wherever the new project sits).
5. In Game1.cs: GumService.Default.Initialize(this) in Initialize() for code-only defaults, GumUI.Update(gameTime) in Update, GumUI.Draw() in Draw. For a .gumx-loading project instead, pass the project's relative path as Initialize's second argument and mirror the Content\<ProjectFolder>\**\*.* CopyToOutputDirectory item group from MonoGameGumFormsSample.csproj.
6. To open it in Visual Studio, create a solution: dotnet new sln -n <ProjectName> then dotnet sln add <ProjectName>.csproj — add the game project first. dotnet sln add pulls in its ProjectReferences (MonoGameGum.csproj, GumCommon.csproj, ...) automatically, but whichever project lands first in the solution becomes the VS startup project — if a referenced library ends up first, F5 does nothing useful (it tries to launch a library, not the game). Newer .NET SDKs generate a .slnx (XML) file instead of .sln — same rule applies.

Verified: this recipe builds clean (0 new errors) against Gum's current source tree.