TST: cover attitude conversion helpers

[ting-hong-shieh]

Summary

• add direct coverage for quaternion-to-precession, nutation, and spin conversions using array inputs, matching how Flight evaluates recorded quaternion data
• cover normalization for both scaled and zero-magnitude quaternions
• leave production code unchanged

This is one focused coverage slice for #709.

Before and after

	Merge base	Head
Full SHA	1d04bcc3b6339bc16f3daf34195943cf9a73f2fa	cb11b9e280fe4dc374df0cd46f8090c4a8706c63
tests/unit/test_tools.py	28 passed	30 passed
rocketpy/tools.py coverage	48% (149/313 statements)	50% (157/313 statements)
Missed statements	164	156

Both measurements used:

python -m coverage erase
python -m coverage run --source=rocketpy -m pytest tests/unit/test_tools.py -q
python -m coverage report -m rocketpy/tools.py

The angle and normalization assertions use pytest.approx defaults (rel=1e-6, abs=1e-12). The five existing weather-data warnings were unchanged between the base and head runs.

Validation

python -m coverage run --source=rocketpy -m pytest tests/unit/test_tools.py -q
# 30 passed, 5 warnings

python -m ruff check tests/unit/test_tools.py
# All checks passed!

python -m ruff format --check tests/unit/test_tools.py
# 1 file already formatted

Environment

• Python 3.12.6
• RocketPy 1.13.0
• NumPy 2.5.2
• SciPy 1.18.0
• pytest 9.1.1
• macOS 26.5.2 (arm64)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.51%. Comparing base (e0ff281) to head (cb11b9e).
⚠️ Report is 61 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1159      +/-   ##
===========================================
+ Coverage    82.18%   83.51%   +1.33%     
===========================================
  Files          122      130       +8     
  Lines        16355    17082     +727     
===========================================
+ Hits         13441    14266     +825     
+ Misses        2914     2816      -98     

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