Upgrade google-java-format to 1.36.1

[DanielThomas]

Summary

• upgrade the relocated google-java-format implementation from 1.35.0 to 1.36.1
• rebase the jfmt layout policy as an explicit patch over the upstream source baseline
• add a reproducible vendoring script and source manifest for future upgrades
• relocate the new commonmark-java dependency and update third-party notices and licenses
• add coverage for Markdown Javadoc formatting introduced upstream

Vendoring

vendor/update-google-java-format downloads the published source artifacts, selects and relocates the formatter sources and dependencies, then applies vendor/google-java-format.patch. Running it against this branch reproduces the committed source tree with no diff.

Testing

• ja compile --recompile
• ja test --all (158 tests)
• vendor/update-google-java-format && git diff --exit-code
• ran the upgraded source formatter against the ja source module; no syntax diagnostics