docs: use concise connection notation in tutorials

[starktech23]

Summary

• replaces verbose connection objects with the concise "source -> target" notation in BARTIQ tutorial notebooks
• updated the corresponding JSON and YAML example inputs
• preserved linked_params, which use a different schema
• left generated compiled QREF outputs unchanged

The updated JSON and YAML inputs normalize to the same QREF models as before, so this change does not alter the represented routines or their resource models.

Validation

• poetry run pre-commit run -a
• poetry run pytest
• poetry run mkdocs build
• executed all top-level tutorial notebooks
• executed docs/tutorials/2025_ieee_qw/01_intro_to_bartiq.ipynb
• verified that the updated examples produce unchanged normalized QREF models

Closes #91

[cla-bot]

Thank you for your pull request! We require contributors to sign our Contributor License Agreement, and we don"t have one on file for you. In order for us to review and merge your code, please contact mstechly@psiquantum.com to get yourself added. (CLA has not been signed by @starktech23)

[mstechly]

Hi @starktech23 ! As mentioned in this message, I'm waiting for an e-mail from you :)

[mstechly]

@starktech23 I added you to the CLA list, could you push an empty commit to trigger the job again?