Included tests to run test --clean from include_dir projects

README.md

@@ -440,7 +440,11 @@ Upload these to a Gitea release. The script requires `build-essential`,
 cargo test
 ```
 
-642 tests (137 unit + 505 integration), ~4 seconds, zero warnings.
+642 unit/integration tests plus 7 end-to-end tests, zero warnings. The e2e
+tests generate real projects and compile their C++ test suites, catching
+build-system issues like missing linker flags and include paths. They require
+cmake and a C++ compiler; if those tools are not installed, the compile tests
+skip gracefully and everything else still passes.
 
 ---