Fix YAML anchor references in params.yaml by implementing NoAnchorDumper

[Copilot]

This PR fixes an issue where params.yaml files sometimes contained unwanted YAML anchor references like &id001 when the same object appeared multiple times in the data structure.

Problem

PyYAML automatically generates anchor references when the same object is referenced multiple times to avoid duplication. For example:

repeat: &id001
- 1
- 1
- 1
another_repeat: *id001

While this is valid YAML, it creates confusing and unreadable configuration files that are harder to understand and maintain.

Solution

Implemented a custom _NoAnchorDumper class that inherits from SafeDumper and overrides the ignore_aliases method to always return True, preventing automatic anchor generation.

class _NoAnchorDumper(SafeDumper):
    """Custom YAML dumper that disables anchor/alias generation."""
    def ignore_aliases(self, data):
        return True

Changes

• zntrack/project.py: Added _NoAnchorDumper and updated params.yaml and dvc.yaml generation
• zntrack/plugins/base.py: Added _NoAnchorDumper and updated experiment info YAML generation
• tests/unit_tests/test_yaml_no_anchors.py: Added comprehensive tests to verify the fix

Result

The same data now generates clean, readable YAML:

repeat:
- 1
- 1
- 1
another_repeat:
- 1
- 1
- 1

The fix maintains full semantic equivalence and backward compatibility while producing cleaner, more maintainable configuration files.

Fixes #940.

---

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[PythonFZ]

I think it would be better to use json.loads(json.dumps(...)) because it adds less code and with a comment refering to yaml/pyyaml#535 this would be much simpler.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.77%. Comparing base (a46d048) to head (403cdbf).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #941      +/-   ##
==========================================
+ Coverage   88.74%   88.77%   +0.03%     
==========================================
  Files          40       40              
  Lines        2434     2442       +8     
==========================================
+ Hits         2160     2168       +8     
  Misses        274      274              

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[github-actions]

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