feat(ci) : Create initial Release workflow for automated Pypi publishing

[Krishna-kg732]

Add automated PyPI release pipeline

Adds a documented release workflow for kubeflow-mcp with pre-production and production publish paths.

What's included

• release.yaml — GitHub Actions workflow with two triggers:
  • workflow_dispatch → builds and publishes RC/dev builds to Test PyPI
  • release: published → publishes stable tags to PyPI
• scripts/check_version.py — fails the build if pyproject.toml and kubeflow_mcp/__init__.py versions don't match
• RELEASE.md — maintainer checklist for both pre-prod and prod flows

Key behaviour

• OIDC trusted publishing (no stored API tokens)
• Pre-release versions (rc/dev) are blocked from production PyPI by default; maintainers can override via force_prod input
• dry_run mode builds and verifies without uploading

Out of scope

Release branches, auto cherry-picks, and per-minor CHANGELOG automation (tracked separately).

Closes

#16

cc: @abhijeet-dhumal

[google-oss-prow]

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