.githooks/pre-commit runs bash syntax check, shfmt format check,
shellcheck, and go vet against staged files on every commit.
Catches the same issues as check.yml before they reach GitHub.
Also update CONTRIBUTING.md setup instructions to include
`git config core.hooksPath .githooks`.
- Add .golangci.yml configuration enabling govet, staticcheck, errcheck, gosimple, ineffassign, unused, gofmt, and goimports linters
- Update scripts/check.sh to run golangci-lint with go vet fallback
- Update CI workflow to install golangci-lint in both format and quality jobs
- Add golangci-lint to CONTRIBUTING.md setup instructions
Closes#266
