[APPS] Add e2e test and frontend/ archive prefix for apps plugin

[sdkennedy2]

Motivation

Prepares the apps plugin archive structure for the upcoming backend functions feature. The downstream branch (sdkennedy2/apps-backend-functions-upload-v2) expects frontend assets to live under a frontend/ subdirectory in the upload archive, alongside backend/ for backend function outputs. This PR moves that prefixing into the parent branch so the archive structure is consistent regardless of whether backend functions are present.

The backend API endpoint has already been updated to accept frontend assets in a subfolder, so this change is safe to land independently.

Changes

• Archive structure: All collected assets are now prefixed with frontend/ before being added to the upload archive. Previously, assets were placed at the root of the zip.
• E2e test: Added an e2e test that builds the apps plugin fixture, verifies the upload request is sent correctly, and extracts the uploaded zip to assert all files live under frontend/.
• Unit test: Updated createArchive assertions to expect the frontend/-prefixed paths.

QA Instructions

1. Run yarn test:unit packages/plugins/apps — all unit tests should pass
2. Run yarn test:e2e packages/tests/src/e2e/appsPlugin --project "chrome | webpack" — e2e tests should pass, including the new archive structure verification

Blast Radius

• Only affects the apps plugin upload archive structure. No other plugins are impacted.
• The change is behind the apps.enable config flag, so no impact to users who don't use the apps plugin.
• The backend API already supports the frontend/ subfolder structure, so no coordination with backend deploys is needed.

Documentation

• How to reliably make frontend production changes
• PR Description Guidelines
• Deploy steps

[sdkennedy2]

• [APPS] Add vite dev server middleware for backend functions #291
• [APPS] Inject backend functions as host build entry points (Phase 1: Rollup/Vite) #289
• [APPS] Add e2e test and frontend/ archive prefix for apps plugin #290 👈 (View in Graphite)
• master

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[sarenji]

Does running the test output a file into this folder, and is this file tracked by git? Couldn't we create a temporary folder instead?

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About mocking in general, looking at how Playwright mocks requests, seems like we could also handle it via page.route, including a page.waitForResponse to monitor the network call and verify the response. More detailed documentation in their Network page.

[sdkennedy2]

Good call 👍. I can take a look at this.

[sarenji]

Is there an explanation for this increase?

[sdkennedy2]

The e2e CI/CD job is very flaky. It can take between 5-30 minutes. It seems primarily because it can take a while to install playwright if it isn't cached.

[sarenji]

LGTM.

If the upload-capture.json file is not tracked by git after running the e2e test locally then this is fine to merge. If not then I'd encourage pursuing one of the solutions I commented about.