Update agent configurations: change commiter mode to all, rename
engineer agent to "Penpot Engineer", and remove obsolete testing agent.
Add new read-only planner agent for architecture analysis and planning.
Add four new skills: bat-cat (syntax-highlighted cat clone), fd-find
(fast file finder), jq-json-processor (JSON processor), and ripgrep
(fast text search).
Add fd-find and bat packages to devenv Dockerfile.
Update .gitignore to exclude opencode package-lock and plans directory.
Signed-off-by: Andrey Antukh <niwi@niwi.nz>
