Adding early version of unfinished schema for v4 #3

	name: Check JSON Schema $ref integrity

	on:
	pull_request:
	types: [opened, synchronize, reopened]
	# Optional: only run when schemas or the script change
	paths:
	- "schema/**"
	- ".github/workflows/check-jsonschema.yml"

	permissions:
	contents: read

	jobs:
	check-refs:
	runs-on: ubuntu-latest

	steps:
	- name: Checkout
	uses: actions/checkout@v4

	- name: Set up Python
	uses: actions/setup-python@v5
	with:
	python-version: "3.11"
	cache: "pip"

	# If you already have a requirements file, replace this step with pip install -r ...
	- name: Install dependencies
	run: \|
	pip install -r requirements.txt

	- name: Run $ref checker
	run: \|
	python schema/v4/check_refs.py

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