Disable Chromatic snapshots globally (#2130)

## Summary:

This PR disables Chromatic snapshots globally (in `preview.tsx`) and then enables it in the one `-regression.stories.tsx` file.

Going forward, we can enable snapshots per-file.

We are making this change to address the fact that hte Perseus repo has been burning through our organization-wide Turbosnap budget because even skipped tests contribute to the Turbosnap count when snapshots are enabled (see the support thread that Juan had with Chromatic: https://khanacademy.slack.com/archives/CEA6W0F6F/p1737389339991279?thread_ts=1737389278.405609&cid=CEA6W0F6F). Specifically, in our Perseus repo we use `onlyStoryFiles`:

> OnlyStoryNames, OnlyStoryFiles work exactly like TurboSnap. The bypassed snapshots (skipping 366 tests) are counted and charged as TurboSnaps.

| Before | After |
| ------ | ----- |
| <img width="920" alt="original" src="https://github.com/user-attachments/assets/1a4db65c-dee6-4d15-9e20-743a3eae1394" /> | <img width="956" alt="after" src="https://github.com/user-attachments/assets/8bdb7edb-3726-4a20-9a8a-d003af5b33ec" /> | 



Issue: "none"

## Test plan:

Land the PR and then watch the build and make sure it doesn't write out that it skipped +300 tests.

Author: jeremywiebe

Reviewers: jeremywiebe, jandrade, #perseus, nishasy

Required Reviewers:

Approved By: jandrade

Checks: ✅ Publish npm snapshot (ubuntu-latest, 20.x), ✅ Lint, Typecheck, Format, and Test (ubuntu-latest, 20.x), ✅ Check builds for changes in size (ubuntu-latest, 20.x), ✅ Cypress (ubuntu-latest, 20.x), ✅ Publish Storybook to Chromatic (ubuntu-latest, 20.x), ✅ Check for .changeset entries for all changed files (ubuntu-latest, 20.x)

Pull Request URL: #2130

Author: jeremywiebe

.changeset/dull-cars-reply.md

@@ -0,0 +1,5 @@
+---
+"@khanacademy/perseus": patch
+---
+
+Change interactive-graph visual regression stories to Storybook's CSF v3

.changeset/quiet-files-marry.md

@@ -0,0 +1,2 @@
+---
+---

.github/workflows/storybook.yml

@@ -43,7 +43,7 @@ jobs:
                   token: ${{ secrets.GITHUB_TOKEN }}
                   projectToken: ${{ secrets.CHROMATIC_APP_CODE }}
                   autoAcceptChanges: "main"
-                  onlyStoryFiles: "**/*regression.stories.tsx"
+                  onlyStoryFiles: "**/*-regression.stories.tsx"
                   # NOTE: We cannot enable `onlyChanged` because it is
                   # incompatible with `onlyStoryFiles` which we use above.
                   # onlyChanged: true # Enable TurboSnap!

.storybook/preview.tsx

@@ -41,6 +41,16 @@ const preview: Preview = {
     // These parameters apply to all stories, both inside and outside the fixture
     // framework.
     parameters: {
+        // Disables Chromatic's snapshotting on a global level
+        // We disable snapshotting globally because we have enabled
+        // turbosnaps for `-regression.stories.tsx` files. If we have
+        // snapshots enabled globally, we pay for turbosnaps even for
+        // skipped stories/tests (which is all of them).
+        // We then enable snapshots for `-regression.stories.tsx` files in
+        // each of those files (unfortunately, this is how we have to do
+        // it).
+        chromatic: {disableSnapshot: true},
+
         options: {
             storySort: {
                 order: ["Perseus", "PerseusEditor", "Math-Input", "*"],