chore: add a justfile for common dev commands

[splusq]

Wraps the commands already documented in CLAUDE.md so they are discoverable via just --list and harder to get subtly wrong.

recipe	what it runs
just install	uv sync --all-extras
just test	the CI invocation, same --ignore set and marker filter
just test-one <target>	one file or pattern
just lint	usort check + ruff format --check + ruff check
just format	usort format + ruff format
just docs-sync	scripts/sync_env_docs.py --fix

just test deliberately mirrors .github/workflows/test.yml rather than being a simpler pytest tests/, so a green local run means the same thing CI does.

Independent of the RFC 005 work I have open alongside this; split out so it can land or be dropped on its own.

---

Note

Low Risk
Developer-only task runner; no runtime, auth, or deployment behavior changes.

Overview
Adds a root justfile so common OpenEnv dev workflows are listed via just instead of copying commands from docs.

It sets PYTHONPATH=src:envs for recipes and wires just install to uv sync --all-extras. just test runs pytest with the same ignored env tests and marker filter as .github/workflows/test.yml, so local runs match CI. just test-one <target> runs a single file or pattern with the same pytest verbosity options.

^{Reviewed by Cursor Bugbot for commit c3c04f8. Bugbot is set up for automated code reviews on this repo. Configure here.}

[cursor]

Reviewed at c3c04f884500e775512795bc08f5655da7038074. The test recipe currently matches the repository workflow, but the PR body promises lint, format, and docs-sync recipes that are absent from the 23-line justfile, and the file lacks a final newline. Please either add the claimed recipes or narrow the description, add the newline, refresh onto current main, and run exact-head CI (only Bugbot has run). No runtime or alignment concern otherwise.

  

_{Sent by Cursor Automation: Release}