fix(lefthook): exclude docs/** from the format pre-commit job (#135)

## Summary
- The `format` pre-commit job's glob still matched `docs/**`, but
`.oxfmtrc.json` ignores that path — so a docs-only staged commit left
oxfmt with zero targets and it exited 2, rejecting the commit.
- Added `exclude: "docs/**"` to the `format` job to keep lefthook and
oxfmt's ignore rules in sync.

Closes #126

## Test plan
- [x] Staged a docs-only change and ran `lefthook run pre-commit
--command format`: job reports `(skip) no files for inspection`, exit 0.
- [x] Confirmed the `format` job still runs and passes on non-docs
staged files.

Author: V3RON

lefthook.yml

@@ -3,6 +3,7 @@ pre-commit:
   commands:
     format:
       glob: "*.{ts,js,json,md,yml,yaml}"
+      exclude: "docs/**"
       run: pnpm exec oxfmt --check {staged_files}
       fail_text: "Run 'pnpm format' to fix formatting."
     lint: