Harden E2E config link prompt submit

[alfonso-noriega]

WHY are these changes introduced?

No issue.

The app-deploy E2E test can fail while creating its secondary app through app config link. The helper was sending the generated app name as many tiny PTY writes, which can drop characters under busy CI prompt rendering, and it also treated the captured Ink prompt echo as required for progress.

WHAT is this pull request doing?

Writes the app name as one PTY text event, waits briefly for the input to be consumed, and then submits Enter separately so Ink handles Enter as submission. It also avoids waiting for the full app name echo, because Ink line-clearing can make captured prompt output incomplete even when input was received.

How to test your changes?

• pnpm --filter @shopify/e2e lint ✅
• cd packages/e2e && pnpm exec tsc --noEmit --project tsconfig.json ✅
• git diff --check ✅
• CI follow-up: tests/app-deploy.spec.ts:84 passed on this branch. E2E tests (shard 1/2) is still red because the separate dev-hot-reload.spec.ts:42 invalid-config failure remains on main; that is fixed separately in Keep hot reload E2E scopes valid #8069.

Not run locally: credentialed Playwright E2E. I also tried pnpm --filter @shopify/e2e type-check, but it currently fails before this diff on origin/main due unrelated @shopify/organizations / Organization type resolution errors in app and store builds.

Post-release steps

None.

Checklist

• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've considered possible documentation changes
• I've considered analytics changes to measure impact
• The change is user-facing — I've identified the correct bump type (patch for bug fixes · minor for new features · major for breaking changes) and added a changeset with pnpm changeset add

Not user-facing; no changeset added.