test: cover build_archive and add it to the ruff scope

build_archive.py had no lint or test coverage, which is how the obsolete
requirements/pyproject mirror check slipped through unnoticed. Close that gap:

- Add tests/test_build_archive.py: a network-free smoke test that runs the
  manifest check, dependency parsing, tarball build, and re-verification, and
  asserts the moved docs/ files, LICENSE, and package sources are packaged.
- Lint build_archive.py in both the local gate (scripts/check.sh) and the CI
  workflow; fix the one issue this surfaced (unused variable py_bin).
- List the new test in the REQUIRED_FILES manifest.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/test_build_archive.py

@@ -0,0 +1,40 @@
+"""Smoke test for the archive builder (build_archive.py).
+
+Guards the packaging manifest and dependency parsing so regressions -- a moved
+or renamed file, a broken REQUIRED_FILES entry, or the requirements/pyproject
+dependency handling -- fail here in the normal test run instead of only
+surfacing at release time. Runs the pure build steps (no network, no pip).
+"""
+
+import tarfile
+from pathlib import Path
+
+import build_archive
+
+# build_archive.py lives at the repo root, so its directory is the project root.
+PROJECT_ROOT = Path(build_archive.__file__).resolve().parent
+
+
+def test_build_archive_builds_and_verifies(tmp_path):
+    out = tmp_path / "llamacppctl-test.tar.gz"
+
+    # Manifest + dependency declaration must be consistent with the real tree.
+    build_archive.verify_required_files(PROJECT_ROOT)
+    deps = build_archive.verify_dependencies_declared(PROJECT_ROOT)
+    assert deps, "expected runtime dependencies declared in pyproject.toml"
+
+    # Build the tarball and re-open it to verify every required file is present.
+    build_archive.build_tarball(PROJECT_ROOT, out)
+    build_archive.verify_tarball(out)
+    assert out.is_file()
+
+    with tarfile.open(out) as tar:
+        names = set(tar.getnames())
+
+    root = build_archive.ARCHIVE_ROOT_NAME
+    # Docs moved under docs/; LICENSE ships at the archive root; package present.
+    assert f"{root}/docs/BEDIENUNGSANLEITUNG.md" in names
+    assert f"{root}/docs/INSTALL_FROM_ARCHIVE.md" in names
+    assert f"{root}/docs/SECURITY_AND_OPERATIONS.md" in names
+    assert f"{root}/LICENSE" in names
+    assert f"{root}/src/llamacppctl/main.py" in names