fix: reject null bytes in capec_map_enricher CLI arguments

[HarshRajSinghania]

Summary

Reject null bytes in scripts/capec_map_enricher.py CLI path and string arguments so the tool logs a clear error and exits instead of crashing with an unhandled ValueError from pathlib/pathvalidate.

Motivation

Fixes #3502. Maintainer requested validation wrappers around filepath and string arguments after fuzzed inputs with embedded null bytes caused an unhandled crash.

Implementation

• Add validate_filepath_no_nulls() for --capec-json, --input-path, --source-dir, and --output-path.
• Add _validate_no_null_bytes() for --version and --edition.
• Catch argparse.ArgumentTypeError in parse_arguments() and exit with code 1 after logging.
• Keep a defensive post-parse check in main() for the same fields.

Testing

• python3 -m ast parse of both changed files succeeds.
• Added unit tests in tests/scripts/capec_map_enricher_utest.py for path/version null bytes and the two validators.
• Full project pytest was not run here: the repository is too large to clone in this environment and pathvalidate is not installed locally. CI on this PR should run tests/scripts/capec_map_enricher_utest.py.

[sydseter]

@HarshRajSinghania thank you for your contribution. Remember that you have to ask to be assigned before starting work on an issue. Otherwise, thank you!.

There is a complexity issue raised in the script. See:

./scripts/capec_map_enricher.py:274:1: C901 'main' is too complex (13)

[sydseter]

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You should use our default pull-request template when creating pull-request.

I will close this pull-request, but feel free to open a new pull-request in the correct way.