@seveibar Could you review this PR?

Summary

This PR improves pad parsing by:

• Supporting *.Cu layers when parsing pads.
• Allowing pads and holes without labels.
• Avoiding duplicate plated holes.

Testing

• Added tests for:
  • Custom pins
  • Unlabeled pins
• Skipped USB fixture tests if the footprints repo is absent.

Related Issue

Closes #125
/claim #125