Add S3/CloudFront PyPI publish workflow

[paololucchino]

Adds an automated publish pipeline triggered on version tag push (v*).

On tag push:

1. Builds the package with python -m build
2. Uploads wheels and sdist to the wfp-hip-pypi S3 bucket via OIDC (no stored credentials)
3. Regenerates the PEP 503 index.html for the package path

The package is then installable via:
pip install data-bridges-client --extra-index-url https://d2i4vvypvg40rv.cloudfront.net/pypi/

Infrastructure (S3 bucket, CloudFront distribution, OIDC role) was provisioned separately via CDK in hip-data-science-tools.

Successfully tested for tag v7.0.0