Update westeros_report.ipynb for 2025-06 workshop

[khaeru]

• Simplify language.
• Improve maths formatting for clarity.
• Improve code examples for clarity.
• Update/check show_plot() for current plotnine.
• Fix some typos.
• Use semantic line breaks.

How to review

• Read the diff.
• Note that the CI checks all pass.

PR checklist

• Continuous integration checks all ✅
• Add or expand tests; coverage checks both ✅
• Add, expand, or update documentation.
• Update release notes.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.4%. Comparing base (33edac8) to head (e0156a9).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##            main    #953     +/-   ##
=======================================
- Coverage   96.6%   96.4%   -0.3%     
=======================================
  Files         60      60             
  Lines       5135    5135             
=======================================
- Hits        4965    4954     -11     
- Misses       170     181     +11     

see 1 file with indirect coverage changes

[glatterf42]

Without looking at the tests in more detail (and so without understanding why they're failing), I'll approve this PR in case you want to get it to main before tomorrow's workshop session.

Please note that if you want to get the docs build to pass, you can do the same as I did for ixmp: pin pandas to 2.2.3 in doc/requirements.in and let uv compile doc/requirements.txt again.

[glatterf42]

This seems to now be

1.
2.
2.

Is that on purpose or just not finished yet?

[khaeru]

just not finished yet?

This. I also meant to open the PR as a draft and leave it until after I present tomorrow and possibly notice further typos.

[khaeru]

Merging despite 2 failing checks:

• The codecov/project failure seems to be spurious, as no code is changed here that would either increase or reduce coverage.
• The macos-latest tutorials failure is flaky: different tutorials have timed out on each of 4 runs.