fix: score Dockerfile variants

[MkDev11]

Summary

• Normalize suffixed Dockerfile names like Dockerfile.dev and Dockerfile.prod to the configured dockerfile scoring key.
• Preserve existing extension behavior for bare Dockerfile, Makefile, dotted files such as build.mk, and unrelated extensionless files.
• Add regression coverage for Dockerfile variant filenames.

Related Issues

• Follow-up to [Bug] Extensionless configured files like Dockerfile and Makefile are skipped as unsupported #985 / fix: score extensionless configured files #986

Type of Change

• Bug fix
• New feature
• Refactor
• Documentation
• Other (describe below)

Testing

• Tests added/updated
• Manually tested

Commands:

• git diff --check
• ./.venv/bin/pytest tests/test_classes.py -q (blocked locally by existing bittensor import conflict between scalecodec and cyscale)
• Stubbed local import proof that Dockerfile.dev maps to dockerfile and reaches the tree-diff scoring path

Checklist

• Code follows project style guidelines
• Self-review completed
• Changes are documented (if applicable)