Make #[slhx::surface] report a compile-time error when slhx.generated.rs is absent instead of silently expanding to an empty module. Add compile-fail coverage for the missing generated include path.
req: build/004
req: test/003
Add compile-fail coverage for generated APIs: a surface include that exposes only one class must reject references to absent generated class names during cargo check.
req: codegen/001
req: style/002
req: test/003
Add a fixture-backed compile-fail test for generated slhx handler contracts: unknown handles and invalid handler shape fail during cargo check with actionable diagnostics.
req: derive_handler/001
req: test/003
slhx agent