Advance development to 0.6.2.dev0 - #41

Summary

• advance package development to 0.6.2.dev0
• record the verified v0.6.1 OIDC release, public hashes and attestations
• retain v0.6.1 as the stable documentation version and rebuild PyPI links for development main

Verified release

• release commit: 48b9e7d9231b5f6cd018f6e927f81df066258f17
• release run: https://github.com/DaoyuanLi2816/mini-verl/actions/runs/30857762954
• PyPI: https://pypi.org/project/miniverl/0.6.1/
• GitHub Release: https://github.com/DaoyuanLi2816/mini-verl/releases/tag/v0.6.1
• wheel SHA-256: ef9ce5378e43c0d833b782e431248a0838e3841ace76a8b3a08781dd28007918
• sdist SHA-256: e5ffd7917035d1f3878b22415dd357cd47fe16b6c77ffdae260e0b85ad7e050f

Local checks

• packaging and environment utilities: 178 passed
• ruff check/format: passed
• Markdown links: passed
• strict MkDocs: passed
• git diff --check: passed

No frozen result, published tag or adapter revision changes.