fix(expectations): rename expectation signature field (#294)

[antoinemzs]

Proposed changes

• realign keys between contract and produced trace

Testing Instructions

1. Step-by-step how to test
2. Environment or config notes

Related issues

• Closes fix(scope): expectation signatures structured output is not keyed like configured in contract output element #294

Checklist

• I consider the submitted work as finished
• I tested the code for its functionality
• I wrote test cases for the relevant uses case
• I added/update the relevant documentation (either on github or on notion)
• Where necessary I refactored code to improve the overall quality
• For bug fix -> I implemented a test that covers the bug

Further comments

[codecov]

Codecov Report

❌ Patch coverage is 91.66667% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 73.58%. Comparing base (8283bfe) to head (67aba4f).

Files with missing lines	Patch %	Lines
pyoaev/signatures/models.py	87.50%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #293   +/-   ##
=======================================
  Coverage   73.58%   73.58%           
=======================================
  Files          54       54           
  Lines        2404     2404           
=======================================
  Hits         1769     1769           
  Misses        635      635           

Flag	Coverage Δ
connectors	73.58% <91.66%> (ø)

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[Filigran-Automation]

🤖 [AI-generated]

Hey @antoinemzs! 👋 Thanks a lot for opening PR #293 — really appreciate the contribution! 🙏

I just had a quick look and I think the description could be enhanced a little to help reviewers get through it faster. I haven't changed anything in your description — just a gentle, optional suggestion:

Area	What could help	Suggestion
### Proposed changes	The two bullets are still empty	Briefly note what the field was renamed from → to (across pyoaev/apis/signature.py, pyoaev/signatures/models.py, signature_manager.py) and why — e.g. any compatibility/breaking impact for client consumers
### Testing Instructions	Still the template placeholder	Add the concrete steps to verify (e.g. run the test/signatures/... feature & unit tests, expected outcome)
### Related issues	Closes #ISSUE-NUMBER placeholder	Link the tracking issue with a closing keyword, e.g. Closes #123 — every PR should be linked to an issue, and the title is expected to end with the (#issue) reference

💡 If helpful, the contribution conventions / PR template walk through what to include.

No rush at all — thanks again for contributing to the project! 🚀