fix(tests): write CRLF CSV fixtures byte-exact on Windows

[dieterolson]

What does this PR do?

Adds newline="" to the two CRLF CSV fixture writes in tests/test_compare_trackman.py so the fixture bytes reach disk exactly as written on every platform.

Why was this required?

Path.write_text applies default newline translation ("\n" → os.linesep), which turns the fixtures' embedded \r\n into \r\r\n on Windows. The BOM/sep= preamble test (test_handles_excel_sep_preamble_and_bom) then parses 0 shots instead of 2 and fails on every Windows checkout. These fixtures exist to reproduce what TrackMan actually exports, so they must be byte-exact; newline="" disables translation and is a no-op on POSIX.

Automated tests

Test-only change — the module is the coverage: tests/test_compare_trackman.py goes from 34 passed / 1 failed to 35/35 on Windows; unchanged on Linux/macOS.

Manual (human) testing

• Reproduced the failure on Windows 11 before the change (assert 0 == 2 — zero shots parsed from the CRLF fixture).
• After: full module passes on Windows; confirmed via the sibling _write_trackman_csv helper (which already used open(..., newline="")) that this matches the file's existing convention.

Checklist

• Single feature/fix — this PR is scoped to one thing with a clear story above
• Automated tests included — test-only change; the module is the coverage
• Manual testing described — I documented what I verified by hand above
• Python tests pass (uv run pytest tests/ -v)
• Pylint passes (uv run pylint src/openflight/ --fail-under=9)
• Ruff passes (uv run ruff check src/openflight/)
• UI builds (cd ui && npm run build) — not applicable, no UI changes
• UI lint passes (cd ui && npm run lint) — not applicable, no UI changes
• Updated docs or CHANGELOG if needed — test-only, no changelog entry
• No unrelated changes mixed in