CI: quarantine upstream workflows not needed on fork

github-workflows-quarantine/README.md

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+# Quarantined Upstream Workflows
+
+These GitHub Actions workflow files originate from the upstream
+[matplotlib/matplotlib](https://github.com/matplotlib/matplotlib) repository.
+They were moved here from `.github/workflows/` to prevent them from running
+on this fork (MLXPorts/mlx-matplotlib).
+
+## Provenance
+
+- **Upstream repo:** matplotlib/matplotlib
+- **Fork point:** `ea40d72fb0` (Merge pull request #30657)
+- **Upstream HEAD at quarantine time:** `08fe8bc4ad` (Merge pull request #31111)
+- **Quarantine date:** 2026-02-11
+
+## Why quarantined
+
+These workflows are designed for the upstream matplotlib project and cause
+problems when running on a fork:
+
+| File | Trigger | Problem |
+|---|---|---|
+| `nightlies.yml` | cron (daily) | Attempts to upload wheels to Anaconda Cloud; fails because `ANACONDA_TOKEN` is not set. Would publish to `scientific-python-nightly-wheels` if it were. |
+| `stale.yml` | cron (3x/week) | Labels fork PRs as inactive on upstream's schedule. |
+| `stale-tidy.yml` | cron (3x/week) | Closes fork issues as inactive on upstream's schedule. |
+| `cibuildwheel.yml` | push to main | Builds release wheels on every push — expensive CI minutes for a dev fork. |
+| `cygwin.yml` | push to main | Runs Cygwin build/test matrix — not relevant for MLX porting work. |
+| `circleci.yml` | status events | Requires `CIRCLECI_TOKEN` secret that doesn't exist on the fork. |
+| `good-first-issue.yml` | issue labeled | Posts upstream community onboarding text on fork issues. |
+| `pr_welcome.yml` | PR opened | Posts upstream contributor greeting on fork PRs. |
+| `labeler.yml` | PR opened | Auto-labels PRs using upstream's label rules. |
+
+## Modifications from upstream
+
+All files (except `labeler.yml` which was unmodified) had minimal changes from
+upstream — primarily swapping `matplotlib/matplotlib` guards to
+`MLXPorts/mlx-matplotlib` and pinning some action versions. The actual workflow
+logic is upstream's.
+
+## Restoring
+
+To re-enable any of these workflows, move the file back to `.github/workflows/`:
+
+```sh
+git mv github-workflows-quarantine/<file>.yml .github/workflows/<file>.yml
+```
+
+## Workflows still active in `.github/workflows/`
+
+The following workflows remain active because they are useful for development:
+
+- `tests.yml` — test suite on push/PR
+- `linting.yml` — linting on PRs
+- `codeql-analysis.yml` — security scanning
+- `mypy-stubtest.yml` — type checking on PRs
+- `clean_pr.yml` — PR cleanliness checks
+- `do_not_merge.yml` — prevents merging WIP PRs
+- `conflictcheck.yml` — merge conflict detection