Rewrite `scripts/check_copyright.sh` script

[reyammer]

Rewrite the check_copyright.sh script:

• rewrite it in python so that it's more maintainable
• extensions to check: let's keep the existing check for "py|sh|ts"
• dirs to check: python/, rust/, js/. Do not scan tests_data
• it should print which file doesn't have a valid copyright. And exit with 1 if at least one file has no banner.
• should be useable like: uv run check_copyright.sh check (note the check command)

Later on:

• we will include this in one of the workflows so that we can for this automatically
• we will extend it to have update or add (or something similar) to update/add copyright banner when missing

[reyammer]

@ps2181 Interested in helping on this one?

[ps2181]

@reyammer Yes, I'll get started on this. Just to confirm — in the check_copyright.sh file, I should add #!/usr/bin/env python3 at the top and proceed with writing the script in Python?

[reyammer]

Thanks! No we can leave that script on its own (we'll remove it later), and create a new check_copyright.py from scratch. Same guidelines as I shared for the previous bug (use click, format with ruff, typing, etc.).

[ps2181]

@reyammer ok , Thanks!