Forward axis_wavelength from image() through measure() to expose()

[jacobdparker]

@
AbstractImagingSensor.measure() did not forward the wavelength axis to
expose(), which then required image.inputs.wavelength to have exactly one
logical axis. This made SequentialSystem.image() fail for any scene whose
wavelength varies along more than one axis — e.g. several disjoint spectral
lines each sampled by its own wavelength bins.

This surfaces downstream in esis: imaging the synthetic multi-line AIA scene
(esis.flights.f1.data.synth.scene_aia(), axes velocity + wavelength)
through system.image(..., axis_wavelength="velocity") raises
ValueError: ...must have exactly one logical axis under optika 2.0, breaking
the distortion-fit machinery and the docs build.

Change

• measure() gains an axis_wavelength parameter and forwards it to expose().
• image() forwards its axis_wavelength through measure().
• Adds regression test test_measure_axis_wavelength (red before, green after).

Release note

A 2.0.x release including this is needed to unblock esis PR #63 (which pins
optika~=2.0); that PR currently fails its docs build on exactly this bug.

🤖 Generated with Claude Code
@

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.34%. Comparing base (9d38b2c) to head (becfb11).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #178   +/-   ##
=======================================
  Coverage   99.34%   99.34%           
=======================================
  Files         116      116           
  Lines        5967     5983   +16     
=======================================
+ Hits         5928     5944   +16     
  Misses         39       39           

Flag	Coverage Δ
unittests	99.34% <100.00%> (+<0.01%)	⬆️

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[jacobdparker]

Thanks Roy — both addressed in 05809be:

• measure() now lists axis_wavelength immediately after axis (all callers pass it by keyword, so the reorder is behavior-preserving).
• test_measure_axis_wavelength is folded into test_measure as a second block (with renamed locals so it doesn't clobber the parametrized rays/wavelength).

Verified locally: pytest -k measure passes, black + ruff clean. (The red docs/readthedocs.org check is a pre-existing RTD env failure, unrelated to this change.)

[roytsmart]

can you update the rtd os to be ubuntu-lts-latest?

[jacobdparker]

Done in becfb11 — build.os is now ubuntu-lts-latest (the old ubuntu-20.04 RTD image was deprecated, which is what was failing the docs build). RTD should go green on this run.