Add tests for combine and koyo tag import tools

[IliTheButterfly]

Motivation

• Provide automated coverage for the two CLI tools that merge/convert EasyBuilder tags to prevent regressions and ensure deterministic behavior.
• Verify merging, conversion and append/merge semantics across representative test fixtures (hmi_tags0/1/2.csv, koyo_tags.csv).

Description

• Add a new test module tests/test_combine_tools.py which exercises the CLI entrypoints via their main() functions (combine_tags_main, koyo_tags_import_main) using controlled sys.argv values.
• Implement tests for: combining hmi_tags0.csv with hmi_tags1.csv, converting koyo_tags.csv into an EasyBuilder CSV, and importing/merging koyo_tags.csv into hmi_tags0.csv, hmi_tags1.csv, and hmi_tags2.csv.
• All CLI-style tests use --force --strategy skip so runs are deterministic and non-interactive, and assertions check final list sizes and representative tag address/type outcomes (including an expected absent/skipped tag case).
• New file: tests/test_combine_tools.py (adds the five tests and small helper runners that set sys.argv).

Testing

• Ran pytest -q tests/test_combine_tools.py and the new module passed (5 passed).
• Ran the full test suite with pytest -q and all tests passed (23 passed).

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Codex Task