…WordPress#76289)

Three new test cases covering the two bugs fixed in the previous commit.

areNodesEqual — media mismatch treated as equal:
Verifies that a <link> with media="all" and a <link> with media="not all" but the same href and integrity are treated as the same element by the SCS comparator, and that the live DOM element is reused rather than replaced.

areNodesEqual — integrity difference still discriminates:
Confirms that other attributes (integrity) still differentiate elements, ensuring the media-stripping does not over-broaden equality.

applyStyles — dynamically-injected plugin styles never disabled:
Verifies that a <link> without an id attribute, injected via appendChild(), is never disabled on any navigation cycle.

applyStyles — plugin styles not enrolled on A→B→C→A back-navigation:
Verifies that, on return to a cached page whose page.styles snapshot includes the plugin element, applyStyles() does not enroll the plugin element in routerManagedStyles and does not disable it on the subsequent navigation away.

Also updates the existing "should enable included styles and disable others" test to reflect the new enrollment-on-activation model: elements must pass through media="preload" activation before they become candidates for disabling.

Three Playwright tests covering real-browser behavior across all
navigation paths, registered via the test/router-dynamic-styles block.

- runtime-activated deferred stylesheet survives forward navigation
(Bug A: media="not all" → "all" preserved after navigate())

- plugin-injected stylesheet survives forward navigation 
(Bug B: no-id element stays active after navigate())

- plugin-injected stylesheet survives back-navigation A→B→C→A
(Bug B cache regression: cached page.styles may include the plugin element; verifies it is not enrolled and not disabled on re-visit)

Reformat seven expect() chains so the argument sits inline with expect() and the assertion value moves to the next line, matching prettier's preferred style for chained matchers.

No logic change.

Add block.json to register the test/router-dynamic-styles block used by router-dynamic-styles.spec.ts E2E fixtures. Declares viewScriptModule pointing to view.js and render callback pointing to render.php.

Add view.js with the @wordpress/interactivity store for the
test/router-dynamic-styles E2E fixture block.

Implements two style-scenario fixtures:

Bug A: activateDeferredStyle action mutates link.media from "not all"
to "all". The init callback reads --test-deferred-active via
getComputedStyle to verify the sheet survived navigation.

Bug B: init callback appends a <style> element without an id attribute,
simulating plugins like Complianz GDPR that bypass wp_enqueue_style().
sheet.disabled is checked directly after each navigation to confirm
the router never enrolled or disabled this element.

pluginStyleEl is module-scoped so it persists across SPA navigations
without relying on store-state serialisation.

Add render.php for the test/router-dynamic-styles E2E fixture block.

Enqueues deferred-style.css with media="not all" to simulate Bug A
(runtime-activated deferred stylesheets). Resolves sibling post URLs
by alias suffix (-b, -c) matching the titles set by addPostWithBlock,
and outputs all data-testid elements required by the spec:
deferred-style-active, plugin-style-active, activate-deferred-style,
nav-to-b, and nav-to-c.

Remove unused 'actions' and 'callbacks' destructuring from store() call. Collapse two ternary expressions onto single lines to satisfy prettier.

Collapse pluginStyleEl.textContent assignment onto a single line.
Merge the split boolean condition in pluginStyleStatus onto one line
to match prettier's expected formatting.