[M4] add cargoxx run/test/clean

CHANGELOG.md

@@ -78,6 +78,15 @@ All notable changes to cargoxx will be documented in this file.
   and `[build]` honoring `warnings_as_errors` and `sanitizers`. Source
   paths emitted relative to `build/` (i.e. prefixed with `../`).
   Output is deterministic. `tests/codegen_cmake.cpp` covers 11 cases.
+- `cargoxx run [--release] [--bin <name>] [-- <args>...]`,
+  `cargoxx test [--release]`, and `cargoxx clean`. `run` builds first,
+  picks the binary (errors with the available list when the project
+  has multiple bins and `--bin` is omitted), and execs it with the
+  process exit code propagated. `test` invokes
+  `nix develop -c ctest --test-dir build/<profile> --output-on-failure`.
+  `clean` removes `build/` while leaving `Cargoxx.lock` and `flake.lock`
+  intact. End-to-end verified against a freshly-scaffolded project.
+  `tests/cmd_run.cpp` and `tests/cmd_clean.cpp` cover 6 cases.
 - `cargoxx build` (without `--no-build`) now drives the full build:
   `nix develop -c cmake -B build/<profile> -S build -G Ninja
   -DCMAKE_BUILD_TYPE=<Profile>` then `nix develop -c cmake --build`