✅ test(unxts-linalg): cover QuantityMatrix short_name "QM"

[nstarman]

Summary

Adds a printing test module for QuantityMatrix, mirroring the existing Quantity / ParametricQuantity short-name tests. It asserts:

• QuantityMatrix.short_name == "QM" (and via the QM alias)
• the full class name is used by default
• use_short_name=True renders QM(...)

Stacking

Stacked on #795 (which adds short_name = "QM"). Until #795 merges, the diff here also shows that one-line change; it collapses to just the new test once #795 lands in main.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Adds coverage in the unxts.linalg package to ensure QuantityMatrix’s wadler-lindig pretty-printing honors the "QM" short name (and the QM alias), aligning it with existing Quantity / ParametricQuantity short-name behavior.

Changes:

• Add packages/unxts.linalg/tests/test_printing.py to assert default/full-name printing vs use_short_name=True printing for QuantityMatrix.
• Define QuantityMatrix.short_name: ClassVar[str] = "QM" so the printing path can render QM(...) when requested.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
packages/unxts.linalg/tests/test_printing.py	New tests covering QuantityMatrix / QM short-name behavior in wadler-lindig output.
packages/unxts.linalg/src/unxts/linalg/_src/_quantity_matrix.py	Adds short_name = "QM" as a ClassVar for correct short-name pretty-printing.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.07%. Comparing base (be47e8a) to head (1471fb3).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #796      +/-   ##
==========================================
+ Coverage   91.98%   95.07%   +3.09%     
==========================================
  Files          83       53      -30     
  Lines        3766     3086     -680     
  Branches      313      231      -82     
==========================================
- Hits         3464     2934     -530     
+ Misses        227       98     -129     
+ Partials       75       54      -21     

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