Remove copier template scaffolding and references

[vredchenko]

Summary

Removes all remaining copier template scaffolding from the project:

• Deletes .copier-answers.yml template configuration file
• Removes copier from dev dependencies in pyproject.toml
• Updates .github/CONTRIBUTING.md to remove copier template references
• Regenerates uv.lock without copier dependencies

The project was originally scaffolded using the Diamond Light Source Python Copier Template but has now matured beyond needing template updates.

Changes

• Deleted: .copier-answers.yml
• Modified: pyproject.toml (removed copier from dev dependencies)
• Modified: .github/CONTRIBUTING.md (removed template references)
• Modified: uv.lock (regenerated without copier)

Testing

Pre-commit hooks and CI/CD workflows will verify that all checks still pass without copier.