Update breakage: use organization-wide workflow

[MaxenceGollier]

Following JuliaSmoothOptimizers/.github#18.

[Copilot]

Pull request overview

Switches the repository’s breakage checking to use organization-wide reusable GitHub Actions workflows (per JuliaSmoothOptimizers/.github#18), removing the previously in-repo implementation.

Changes:

• Replaced the existing breakage workflow implementation with a call to JuliaSmoothOptimizers/.github reusable workflow.
• Added a workflow_run-triggered workflow to post breakage results/comments using an org-wide reusable workflow.
• Removed the local .breakage Julia project and script previously used to compute dependents.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
.github/workflows/Breakage.yml	Replaced local Breakage job graph with a reusable workflow call.
.github/workflows/CommentBreakage.yml	Added reusable workflow call to comment on PRs after Breakage completes.
.breakage/get_jso_users.jl	Removed (no longer needed with org-wide workflow).
.breakage/Project.toml	Removed (no longer needed with org-wide workflow).

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[Copilot]

The called reusable workflow likely needs to download artifacts from the triggering Breakage run and post a PR comment. Because reusable workflows cannot increase GITHUB_TOKEN permissions beyond what the caller grants, this workflow should explicitly set appropriate top-level permissions (e.g., pull-requests: write and actions: read, plus contents: read) to avoid failures in repos where the default token permission is read-only.

Suggested change

	permissions:
	contents: read
	actions: read
	pull-requests: write

[MaxenceGollier]

I don't understand this comment.