- add .editorconfig for indent, whitespace, and file-type rules
- add project-local .vimrc to enforce Vim settings via exrc
- add .clang-format for C/C++ style presets and list formatting
- add devtools/format-code.sh to run clang-format and fixups
- adjust clang-format config for stable, idempotent output
- update AGENTS.md with new formatting strategy
- add .git-blame-ignore-revs entry for format change commit
This commit sets up an automated formatting pipeline to let
contributors use their editor of choice while ensuring
consistent, stable code style across the project.
