Add tooling

[pythoninthegrass]

📑 Description

• .vscode config (whitelisted in .gitignore)
• dependabot (bump dependecies via PRs)
• .tool-versions (asdf for python + poetry)
• poetry (pyproject.toml + poetry.lock)
• editorconfig (soft enforcement of code formatting locally via extension)
• updated docs

✅ Checks

• [X] My pull request adheres to the code style of this project
• [X] My code requires changes to the documentation
• [X] I have updated the documentation as required
• [X] All the tests have passed

ℹ Additional Information

There are optional dev dependencies (icecream, ipython,rich, ruff), but they don't get exported to requirements.txt:

poetry export -f requirements.txt --output requirements.txt --without-hashes

Technically reversed your decision to exclude the .vscode directory, but the rationale is that it's workspace level configs vs. user settings — only modifies vscode behavior at a repo level. Obviously, it's your show, but think it'd be useful for future contributors to have a similar environment.