feat(ruby): add rubocop pre-commit hook entry

Add commented-out rubocop hook for Ruby projects.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: matthew-on-git

.pre-commit-config.yaml

@@ -40,6 +40,13 @@ repos:
   #     - id: terraform_fmt
   #     - id: terraform_tflint
 
+  # --- Ruby (uncomment if languages includes ruby) ---
+  # Linting and formatting with rubocop
+  # - repo: https://github.com/rubocop/rubocop
+  #   rev: v1.73.2
+  #   hooks:
+  #     - id: rubocop
+
   # --- Secret Detection ---
   # Detects hardcoded secrets, API keys, and credentials in code
   - repo: https://github.com/gitleaks/gitleaks