feat(ct): type mount() story ids through a generated Stories registry

[Pavel Feldman (pavelfeldman)]

Summary

• @playwright/test exports an empty Stories interface; mount(id, props) types props and update() from Stories[id] when the id is registered, keeps untyped props otherwise, and the explicit mount<typeof Story>(id, props) form still works.
• A Vite plugin next to the html-reporter gallery generates stories.d.ts (one line per story file, ids prefixed with the package name) and augments Stories; the gallery moves to packages/html-reporter/tests.
• The component testing skill documents both typing forms and includes the plugin.

Fixes #42083

[github-actions]

Test results for "tests 1"

6 flaky

⚠️ [chromium-library] › library/video.spec.ts:736 › screencast › should work with video+trace `@chromium-ubuntu-22.04-node24`
⚠️ [firefox-library] › library/browsercontext-cookies-third-party.spec.ts:257 › third party 'Partitioned;' cookies `@firefox-ubuntu-22.04-node20`
⚠️ [firefox-library] › library/browsercontext-cookies-third-party.spec.ts:470 › top level 'Partitioned;' cookie and same origin iframe `@firefox-ubuntu-22.04-node20`
⚠️ [firefox-page] › page/page-emulate-media.spec.ts:144 › should keep reduced motion and color emulation after reload `@firefox-ubuntu-22.04-node20`
⚠️ [firefox-page] › page/page-event-request.spec.ts:181 › should return response body when Cross-Origin-Opener-Policy is set `@firefox-ubuntu-22.04-node20`
⚠️ [webkit-library] › library/browsercontext-storage-state.spec.ts:655 › should not leave IndexedDB connections open `@webkit-ubuntu-22.04-node20`

51326 passed, 1247 skipped

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Merge workflow run.

[github-actions]

Test results for "MCP"

1 failed
❌ [chrome] › mcp/cli-test.spec.ts:23 › debug test and snapshot @mcp-ubuntu-latest-chrome

8274 passed, 1371 skipped

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Merge workflow run.

[github-actions]

🟢 The one failure is a pre-existing flake — this PR is clear

Hi, I'm the Playwright bot and I took a look at the failing CI on this PR.

Only ubuntu-latest - chrome failed, on a single MCP test: mcp/cli-test.spec.ts:23 › debug test and snapshot. This PR only touches component-testing typing (html-reporter gallery, Stories types, generate_types, and CT skill docs) — nothing under tests/mcp/ or the MCP/CLI product code the test exercises. The same test also flakes on commits this PR can't be responsible for, so I'm calling it noise.

Details

Overall: 43 of 44 checks green. The lone red is one MCP test on Chrome, in a code path the diff doesn't reach. No caused-by-PR failures.

Pre-existing flake / infra

• [chrome] › tests/mcp/cli-test.spec.ts:23:5 › debug test and snapshot — expect(listOutput3).toContain('(no browsers)') failed because a browser context from an earlier test was still attached (tw-bbc164 … browser-type: chromium (attached)), so list reported an open browser instead of (no browsers). That's a state-leak flake, not a typing change.
  • Across the CI results DB this test's final verdict is green in 723/723 Chrome runs — it never fails outright — but it has flaked within a run on commits unrelated to this PR: a push to main (sha bee00ad3) and PR chore(net): use native happy eyeballs instead of the manual implementation #42240. Same (project, file, title), so this PR isn't the cause.
  • The diff is confined to packages/html-reporter/**, packages/playwright/types/test.d.ts, utils/generate_types/**, and the playwright-component-testing skill — none of which the MCP CLI flow imports or touches.

A re-run of the Chrome MCP job should go green.

_{Triaged by the Playwright bot - agent run}