fix(packaging): bundle scripts/python into the wheel core_pack (#3665) (#3670)

`specify init --script py` generated skills that invoke
`python3 .specify/scripts/python/<name>.py`, but the wheel's
force-include list only carried `scripts/bash` and `scripts/powershell`.
Installs from PyPI/Homebrew therefore shipped commands pointing at files
that were never packaged, leaving `--script py` non-functional while
`sh`/`ps` kept working.

Force-include `scripts/python` alongside the other two variants, and add
a contract test that asserts every script variant present in the repo is
bundled, so a future variant cannot be dropped the same way.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

tests/contract/test_wheel_core_pack_scripts.py

@@ -0,0 +1,40 @@
+"""Contract tests for the script variants bundled into the wheel's core_pack.
+
+``specify init --script <type>`` installs from ``specify_cli/core_pack/scripts/``
+when the CLI runs from a wheel. Any script variant that lives in the repository
+must therefore be force-included at build time, otherwise the generated
+commands reference scripts the released package never ships (#3665).
+"""
+
+from __future__ import annotations
+
+import tomllib
+from pathlib import Path
+
+REPO_ROOT = Path(__file__).parents[2]
+
+
+def _force_include() -> dict[str, str]:
+    with (REPO_ROOT / "pyproject.toml").open("rb") as pyproject_file:
+        pyproject = tomllib.load(pyproject_file)
+    return pyproject["tool"]["hatch"]["build"]["targets"]["wheel"]["force-include"]
+
+
+def test_every_script_variant_is_bundled_into_core_pack():
+    force_include = _force_include()
+    variants = sorted(
+        path.name for path in (REPO_ROOT / "scripts").iterdir() if path.is_dir()
+    )
+
+    assert variants, "expected at least one script variant under scripts/"
+    for variant in variants:
+        assert force_include.get(f"scripts/{variant}") == (
+            f"specify_cli/core_pack/scripts/{variant}"
+        ), f"scripts/{variant} is missing from the wheel force-include list"
+
+
+def test_python_script_variant_is_bundled():
+    # Explicit regression guard for #3665: `--script py` shipped skills that
+    # invoked python3 .specify/scripts/python/*.py while the wheel bundled
+    # only the bash and PowerShell variants.
+    assert _force_include()["scripts/python"] == "specify_cli/core_pack/scripts/python"