chore: add pre-commit configuration and CI

[nearlyforget]

Description
This PR introduces a comprehensive pre-commit configuration and a
corresponding GitHub Actions workflow to automate code quality checks,
formatting, and security linting across the repository.

Tools & Hooks Added

• Python (Ruff): Uses the ruff linter and formatter for extremely fast
  Python code quality checks (replaces Black, Flake8, and isort).
• Frontend/Node.js (Prettier): Automatically formats TypeScript, TSX,
  JavaScript, JSON, CSS, and HTML files.
• Documentation: Formats Markdown files and checks for common typos
  using codespell.
• Security: Includes detect-private-key to prevent accidental commits
  of sensitive information.
• General Hygiene: Ensures consistent trailing whitespace removal and
  end-of-file newlines.

CI/CD Integration

• GitHub Actions (linter.yml): A new workflow is added that runs
  these same checks on every push and pull request to the main branch.
  This ensures that no unformatted or lint-failing code is merged.

[0x8000-0000]

How is this different from #16 ?