With client-side media processing, the uploaded filename may be changed
by the server during processing. Update the E2E tests to:

1. Check for a valid HTTP URL instead of the specific UUID filename
2. Check that the image block has a valid ID in the content
3. Remove unused fileName variables

This is necessary because the upload-media module may rename files
during processing (e.g., when the file is a Blob that gets converted
to a File with a default name like 'image.png').

Co-Authored-By: Claude Opus 4.5 <[email protected]>

- Update cover block test to check for HTTP URL instead of filename
  (filename may be changed by server during processing)
- Add is-transient class wait for image tests that publish posts
  (ensures thumbnail generation is complete before publish)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Add explicit wait for Publish button to be enabled with 30s timeout
in image upload tests. This ensures all background processing
(thumbnail generation, sideloads) completes before attempting to
publish.

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Complete the window global rename started in 01c7971
by updating use-upload-save-lock and media-upload utils.

Add test plugin to disable client-side media processing
for tests incompatible with cross-origin isolation (COEP/
COOP headers). Update cross-origin isolation tests to
expect isolation enabled by default.

Co-Authored-By: Claude Opus 4.6 <[email protected]>

- Add upload-media store queue wait in site editor image upload test
  to handle async client-side processing completing before checking src
- Fix big-image-size-threshold test: make original_image assertion
  conditional since client-side scaling may not set this metadata
  (it's a server-side behavior during wp_create_image_subsizes)
- Move dimension assertions outside the -scaled suffix check since
  both client-side and server-side scaling should respect the threshold

Co-Authored-By: Claude Opus 4.6 <[email protected]>

…d test

Client-side media processing is not yet fully supported in the site
editor context — the upload-media store pipeline gets stuck and items
never leave the queue. Disable it for this test using the existing
test plugin so it can use the traditional server-side upload path.

Co-Authored-By: Claude Opus 4.6 <[email protected]>

Co-Authored-By: Claude Opus 4.6 <[email protected]>

Move gutenberg_is_client_side_media_processing_enabled() from
lib/load.php to lib/compat/wordpress-7.0/media.php per the
convention for release-specific features. Rename the filter
from gutenberg_ to wp_ prefix for Core migration.

These were development-only helpers that are no longer needed
for the graduated client-side media processing feature.

The feature is no longer experimental, so the variable name
should reflect its actual purpose.

This JS global is no longer experimental. Moving it to
lib/media/load.php which already gates on the feature
being enabled.

Rename __experimentalMediaProcessing to __clientSideMediaProcessing in
image block edit.js, and remove gutenberg-media-processing from test
bootstrap experiments since the feature is now graduated.

Co-Authored-By: Claude Opus 4.6 <[email protected]>

COEP headers break TinyMCE iframe initialization, causing
the wp-editor meta box E2E test to fail. This matches the
fix already applied in the classic block test.

COOP headers cause browsing context replacement during page
navigations, breaking Playwright's page reference. This
affects template creation and revert tests in both the post
editor and site editor.

The call was at the top level of the file, executing during
plugin load before enqueue hooks fire. Wrap it in a function
hooked to admin_init, matching the pattern in editor-settings.php.

The filter check at file-load time runs before other plugins
can register their filters. Re-check at action time so the
disable plugin works. Also disable client-side media
processing in pattern E2E tests to prevent COEP from
breaking page navigations.