Only Run Chromatic based on a label

[mannycarrera4]

🐛 Bug Report

Right now we run chromatic on every commit to a PR, we should only run it manually when a label is added so decreased the amount of snapshots run.

There's a few ways for us to do this:

• We can add a label like [skip chromatic] that will skip the CI chromatic run
• Or given the label [run chromatic] that only runs chromatic when the label is present and on every commit

[alanbsmith]

What’s costing you today

In pull-request.yml, visual-test runs on every pull_request synchronize:

• Build Storybook → restore docs → Chromatic with storybookBuildDir: docs
• No onlyChanged / TurboSnap
• No workflow concurrency / cancel-in-progress
• No draft / path / bot skips

So rapid force-pushes, docs-only commits, and Dependabot-style noise all still burn a full bill.

Highest-impact levers

Lever	Impact	Effort	Notes
TurboSnap (onlyChanged: true)	High	Medium	Only re-capture stories on the changed dependency graph; unchanged stories become TurboSnaps (~1/5 cost → often ~60–80% savings). You already have fetch-depth: 0. You’ll need Storybook build stats (preview-stats.json) and externals for tokens/global CSS/fonts.
Cancel superseded runs	High	Low	concurrency + cancel-in-progress so only the latest commit’s Chromatic finishes.
Run Chromatic less often	High	Low–Med	Skip drafts, Dependabot; path-filter non-UI PRs; or gate on ready_for_review / a label.
Trim snapshot surface	Med	Med	~50 opted-in files already; multi-viewport stories (e.g. Modal/Tabs) multiply captures.
exitOnceUploaded: true	Low for quota	Low	Canary already uses this — saves Actions minutes, not snapshots.

Practical recommendation

1. This week: concurrency cancel + skip drafts/bots (and path filters if you’re OK being a bit looser on visual coverage for non-UI PRs).
2. Biggest ROI: enable TurboSnap and validate on a few real PRs — especially ones that only touch one package vs. tokens/preview, where TurboSnap can over-rebuild if externals aren’t set.

One caveat: TurboSnap has historically been finicky with the pull_request merge-commit trigger (Chromatic has preferred push). Worth a controlled pilot before treating it as “set and forget.”