Fix pre-commit hooks to only check staged files

Problem

Pre-commit hooks currently run on all files in the repository:

pre-commit:
  commands:
    lint:
      run: npm run lint           # ❌ Runs on src/**/*.ts
    format:
      run: npm run format         # ❌ Runs on src/**/*.ts  
    test:
      run: npm run test:quick     # ❌ Runs all tests

This prevents committing clean new code when pre-existing broken files exist.

Impact

• Blocks commits even when staged files are error-free
• Forces fixing ALL codebase errors before ANY commit
• Inefficient for incremental fixes
• Standard practice is to only lint/format staged files

Solution

Update lefthook.yml to use {staged_files}:

pre-commit:
  commands:
    lint:
      glob: "*.{ts,js,tsx,jsx}"
      run: npx eslint {staged_files} --max-warnings=0
    format:
      glob: "*.{ts,js,tsx,jsx,json,md,yml,yaml}"
      run: npx prettier --write {staged_files}
    test:
      glob: "*.{ts,js,tsx,jsx}"
      run: npm run test:quick -- {staged_files}

Benefits

• ✅ Only validates files being committed
• ✅ Allows incremental codebase cleanup
• ✅ Faster hook execution
• ✅ Industry standard practice
• ✅ Unblocks GitLab Wiki Manager commit

Acceptance Criteria

• Hooks only run on staged files
• Clean files can be committed despite other errors
• GitLab Wiki Manager files commit successfully