Rewire import e2e test to a hosted Jetpack backup

[gcsecsey]

Related issues

• Related to STU-1866 (completes its last acceptance criterion: import tests updated) and STU-1870
• Stacked on Add manifest-driven prep script for hosted data-heavy e2e fixtures #4152

How AI was used in this PR

Claude Code seeded the source site's content, pre-flighted the artifact through real CLI imports (which surfaced a platform drop-in bug — Linear issue incoming), and implemented the rewire under my direction; I reviewed the result.

Proposed Changes

import.test.ts — the release-time test that imports a genuine WordPress.com Jetpack backup — has silently skipped in CI since it was written: its archive had to be fetched by hand from an internal P2, and the files there went stale. The minimal fixture in import-formats.test.ts covers the format's shape; this test's distinct job is catching drift in what customer backups actually contain, so it needs a real, current artifact.

• The test consumes test-fixtures/downloads/coolbeans-jetpack-backup-2026-07.tar.gz, fetched by the Add manifest-driven prep script for hosted data-heavy e2e fixtures #4152 pipeline from the fixtures site. Locally it still skips with an actionable message when the file is absent; in CI the prep step hard-fails first, so the silent-skip era ends.
• The backup is a genuine Jetpack Cloud export (149 MB, 51 per-table SQL files incl. WooCommerce tables, full uploads tree, wpcomsh mu-plugins, __wp__ core dir) of Cool Beans (gcsecseywoa11.wpcomstaging.com), a purpose-built public test site whose content is self-describing: a hero post stating the site's purpose, encoding-test posts (ASCII and UTF-8/emoji), a long-form truncation canary, media/taxonomy/comment-thread tests, and nested pages.
• Assertions verify the imported site really serves the backup: blog name + tagline in the page title, the custom theme's landing page rendering, and the hero post resolving at its pretty permalink (which also proves the permalink structure imported).
• One sanitization, documented in the manifest: the archive's wp-content/object-cache.php (WP.com platform Memcached drop-in) is removed — importing it fatals the local site. That importer gap is being filed separately; once fixed, an unsanitized copy should become the regression fixture. Everything else, including wpcomsh and the core tree, is kept for realism.
• The stale apps/studio/e2e/imports/ directory, its P2-pointing readme, and its .gitignore entries are removed.

Verified end to end

• npm run e2e:fixtures downloads the wrapper from the live fixtures site, verifies both SHA-256 hashes, unwraps; a second run verified-skips both fixtures.
• Pre-flight of this exact artifact through the real CLI: import exits 0, wp option get blogname → Cool Beans, started site serves HTTP 200 with the full title, theme landing renders, hero permalink returns 200 with the checklist text — i.e., every assertion in this PR's test, validated against the shipped artifact.

Testing Instructions

1. npm run e2e:fixtures — downloads + verifies both hosted fixtures (~150 MB).
2. This PR's e2e CI runs import.test.ts for real for the first time — the E2E jobs are the authoritative proof (note: they now download the artifact; mac/windows cache it keyed on the manifest, Linux fetches per run).

Pre-merge Checklist

• Have you checked for TypeScript, React or other console errors?