Add docs, unit tests, and refactor repro test infra #10054

	name: Invalidations

	on:
	pull_request:

	concurrency:
	# Skip intermediate builds: always.
	# Cancel intermediate builds: always.
	group: ${{ github.workflow }}-${{ github.ref }}
	cancel-in-progress: true

	jobs:
	evaluate:
	# Only run on PRs to the default branch.
	# In the PR trigger above branches can be specified only explicitly whereas this check should work for master, main, or any other default branch
	if: github.base_ref == github.event.repository.default_branch
	runs-on: ubuntu-latest
	steps:
	- uses: julia-actions/setup-julia@v2
	with:
	version: '1.10'
	- uses: actions/checkout@v4
	- uses: julia-actions/julia-buildpkg@v1
	- uses: julia-actions/julia-invalidations@v1
	id: invs_pr

	- uses: actions/checkout@v4
	with:
	ref: ${{ github.event.repository.default_branch }}
	- uses: julia-actions/julia-buildpkg@v1
	- uses: julia-actions/julia-invalidations@v1
	id: invs_default

	- name: Report invalidation counts
	run: \|
	echo "Invalidations on default branch: ${{ steps.invs_default.outputs.total }} (${{ steps.invs_default.outputs.deps }} via deps)" >> $GITHUB_STEP_SUMMARY
	echo "This branch: ${{ steps.invs_pr.outputs.total }} (${{ steps.invs_pr.outputs.deps }} via deps)" >> $GITHUB_STEP_SUMMARY
	- name: Check if the PR does increase number of invalidations
	if: steps.invs_pr.outputs.total > steps.invs_default.outputs.total
	run: exit 1

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