ci: add post-merge auto-format GitHub Actions workflow

[openroad-ci]

Summary

Run clang-format, buildifier, black, and tclfmt on files changed in each push to master, committing any fixes automatically.

Type of Change

• New feature

Impact

A step towards automating these steps

Verification

• I have verified that the local build succeeds (./etc/Build.sh).
• I have run the relevant tests and they pass.
• My code follows the repository's formatting guidelines.
• I have signed my commits (DCO).

[gemini-code-assist]

Note

Gemini is unable to generate a review for this pull request due to the file types involved not being currently supported.

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"

[oharboe]

😌

use bazel to do this so it can be replicated locally, I think it will save work and frustrations nd be more robust. bazelisk run //:fix_lint is all that should happen in this just + commit

also, bazel minimizes docker config github ci hell. just test and minimize config required locally and you are done. no docker image hell.

@nekronos Thoughts? You are the expert on implementation here

[maliberty]

fix_lint only does tclfmt/tclint afaik, while this also does clang-format, black, buildifier, and lock file updating.

[oharboe]

fix_lint only does tclfmt/tclint afaik, while this also does clang-format, black, buildifier, and lock file updating.

move all those into fix_lint

[nekronos]

😌

use bazel to do this so it can be replicated locally, I think it will save work and frustrations nd be more robust. bazelisk run //:fix_lint is all that should happen in this just + commit

Yes, best to make it reproducible across CI/local

also, bazel minimizes docker config github ci hell. just test and minimize config required locally and you are done. no docker image hell.

Also a benefit of making available as a bazel target

@nekronos Thoughts? You are the expert on implementation here

[maliberty]

When all those things are in bazel I'm fine to convert but I think this can still be merged as is until then.

[oharboe]

When all those things are in bazel I'm fine to convert but I think this can still be merged as is until then.

👍