fix: inspect types when resolving field marshallers for structured types

[seandstewart]

• Fixes an issue where two structured types within the same graph have conflicting attribute names, resulting in incorrect marshaller assignment for those fields.
• Fix some issues with job duplication in CI

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 97.43590% with 1 line in your changes missing coverage. Please review.

Project coverage is 96.77%. Comparing base (9a9a2ba) to head (a5ddf68).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/typelib/marshals/routines.py	94.73%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main       #2   +/-   ##
=======================================
  Coverage   96.76%   96.77%           
=======================================
  Files          21       21           
  Lines        1454     1489   +35     
  Branches      260      265    +5     
=======================================
+ Hits         1407     1441   +34     
- Misses         27       28    +1     
  Partials       20       20           

Flag	Coverage Δ
unittests	96.50% <97.43%> (+0.01%)	⬆️

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