upgrade tooling (uv, ruff, pnpm)

[krmax44]

• 🔧 upgrade tooling, use pyproject.toml
• 🔧 switch to pnpm, add froide as peer dependency
• 🔧 update eslint
• 👷 update ci to match new tooling
• 🚨 fix linter errors, formatting
• 🔧 add version and dependencies to pyproject.toml
• 📦 only ship po locale files