Add pre-commit hooks and update dev docs

[mahmoud]

• Add .pre-commit-config.yaml with three hooks:

  • prettier: auto-formats staged frontend/src/ files
  • eslint: lints staged frontend/src/ files
  • ruff (v0.15.5): checks Python syntax errors and undefined names (E9, F63, F7, F821) in montage/

• Add pyproject.toml with ruff line-length config

• Update dev.md:

  • Add OAuth setup section explaining both modes (debug bypass vs real OAuth) with step-by-step registration instructions
  • Link to MediaWiki OAuth developer guide and Toolforge docs
  • Add pre-commit hooks setup section
  • Add CI section with local check commands
  • Add lint:check and format:check to frontend commands list
  • Fix Node.js version requirement (v16 -> v20)
  • Remove .env from project structure (gitignored file)

• Update README.md:

  • Add CI badge
  • Add Development section linking to dev.md
  • Replace outdated tox instructions with Docker-based test command
  • Add Deployment section linking to deployment.md

• Fix view_jurors -> view_juror typo in rendered_admin.py (ruff F821 caught this: route referenced view_juror but function was named view_jurors)