[StevenTCramer]

Summary

What changed

• New ResultValueKind (MaybeNull, ValueType, Enum) in
  source/timewarp-nuru-analyzers/generators/models/result-value-kind.cs, read from the ITypeSymbol by
  ResultValueKinds.Of (Nullable<T> stays MaybeNull).
• HandlerReturnType.ValueKind (the result, or T of Task<T>) and HandlerDefinition.SuccessValueKind (problem
  pair success type), set by every extractor that builds a return type: lambda expression and block bodies, method
  groups, [NuruRoute] command classes (IQuery<T>/ICommand<T>), and [Operation] mediator endpoints.
  HandlerDefinition.RenderedValueKind picks the one the invoker writes.
• HandlerInvokerEmitter.EmitResultOutput skips is not null for any non-nullable value type, and the JSON
  fallback writes result.ToString() with no ?. for one. GetOutputStrategy sends a non-nullable enum to
  Raw, so an enum result prints its member name (Dark) instead of JSON; capabilities now reports such a route's
  returnType kind as Primitive. User structs keep the JSON strategy.
• Decision: enums print raw. JSON of an enum is its number (no converter in the built-in contexts), which is worse
  for a CLI than the member name, and matches how the binder takes enum input by name.
• Tests: generator-75 now returns the enum and the struct directly (the 529 workaround shade.ToString() is gone)
  and adds an async enum delegate and an enum method group; new tests/timewarp-nuru-tests/routing/routing-39-value-type-results.cs
  pins runtime output (delegate, async delegate, method group, IQuery<TEnum> endpoint, user struct,
  Nullable<TEnum> null writes nothing) in the CI multi-mode assembly.
• Audit boy-scout: ganda repo audit --fix set the VS Code window title/icon in the git-ignored
  .vscode/settings.json (advisory vscode-window-icon warning); nothing to commit.

Follow-up (not fixed here)

• A delegate or method-group result whose type is declared in a namespace the generated file does not import
  fails with CS0246: GetReturnTypeName/GetUnwrappedReturnTypeName and EmitRender declare the result local by
  ShortTypeName (minimally qualified). It hits reference types too, so it is its own defect; routing-39 keeps its
  result types in the global namespace for that reason. Worth a separate task (fully qualified names need the
  nullable reference ? kept, or var).

Gates

Gate	Command	Result
Build	./bin/dev build	pass (exit 0); fix pass 1 rerun: pass (exit 0)
Test	ganda runfile cache --clear then ./bin/dev test	pass (exit 0; CI multi-mode incl. routing-39, standalone incl. generator-75 6/6); fix pass 1 rerun: pass (exit 0, 0 failed)
Audit	ganda repo audit	pass; first run had one advisory vscode-window-icon warning, fixed with --fix, rerun "Repository passes all audit checks."; fix pass 1 rerun: pass (exit 0, "Repository passes all audit checks.")

Test plan

Smoke:

ganda runfile cache --clear
dotnet run tests/timewarp-nuru-tests/routing/routing-39-value-type-results.cs
dotnet run tests/timewarp-nuru-tests/generator/generator-75-consumer-surface-no-ivt.cs

Expect: routing-39 6/6 pass (vtr-mode Dark prints Dark, the IQuery<VtrShade> endpoint prints Light,
the struct writes both members, the null VtrShade? writes nothing); generator-75 6/6 pass, with
.WithHandler((Gen75Shade shade) => shade) compiling as a consumer. In
artifacts/generated/routing-39-value-type-results.cs/.../NuruGenerated.g.cs the enum route emits
app.Terminal.WriteLine(result.ToString()); with no if (result is not null), and the struct's JSON fallback is
result.ToString() with no ?..

Kanban task 583
Session: 1411579