Generalize parser tests and drop bundled fixtures

[kaklik]

Summary

• rename the parser test module to the more neutral test_parser.py
• make the parser tests iterate over any non-hidden fixtures placed in data/ and skip cleanly when none exist
• remove the bundled sample logs and leave an empty placeholder so external fixtures can be supplied separately

Testing

• pytest

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https://chatgpt.com/codex/tasks/task_e_68f2bbfc2b7083228d45f84e327fe5b7