Add C3D file loader

[Aadit-Khurana]

Description

What is this PR

• Bug fix
• Addition of a new feature
• Other

Why is this PR needed?

Closes #299.
There is currently no native way to load .c3d files into movement.

What does this PR do?

Adds a new C3D loader using ezc3d.
Bypasses header errors by extracting the core point matrix directly.
Shuffles the raw axes and successfully packages the data into the required movement xarray.Dataset format with dimensions ["time", "space", "keypoints", "individuals"].

References

Closes #299

How has this PR been tested?

Tested locally to extract and format a 3D dataset.
Added unit tests in tests/test_unit/test_io/test_load_c3d.py to ensure it gracefully handles missing files (FileNotFoundError) and invalid/corrupted files (ValueError).

Is this a breaking change?

No.

Does this PR require an update to the documentation?

Yes
The supported formats table in the user guide will need to be updated to include .c3d. (Will add this once the core loader logic is reviewed).

Checklist:

• The code has been tested locally
• Tests have been added to cover all new functionality
• The documentation has been updated to reflect any changes
• The code has been formatted with pre-commit

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud