Open pyproject version bump PR from release draft

[httpdss]

Summary

Follow-up to #178 after revisiting the release flow:

• Keeps the Release Drafter upgrade to v7.5.1 from Fix release drafter warnings and sync pyproject version #178 for the Node 24 warning cleanup.
• Changes the pyproject version sync from a direct push to main into an automatic version-bump PR created with peter-evans/create-pull-request@v8.1.1.
• This makes the version bump happen after Release Drafter resolves the next draft version, but before the draft release should be published.
• The PyPI workflow from Fix release drafter warnings and sync pyproject version #178 still publishes on release.published and verifies pyproject.toml matches the release tag.

Repo setting checked

The repository already has the required Actions settings for this approach:

• default_workflow_permissions: write
• can_approve_pull_request_reviews: true

That means GITHUB_TOKEN is allowed to create the version-bump PR.

Verification

• actionlint .github/workflows/release-drafter.yaml .github/workflows/publish-pypi.yml → passed
• YAML parse check for both workflows → passed
• Ad-hoc /tmp/hermes-verify-release-workflows.py → passed: release-drafter action version, pyproject bump PR gating, and publish version check match/reject behavior
• git diff --check → passed