same_page_preview 3.0.0-rc1

Release candidate for the Drupal 11-ready rewrite.

Bug Fixes

- Preview now works on node create forms (#3545080) — Fixed three bugs
preventing preview from loading on /node/add/*: missing form class
registration, incorrect route name, and wrong AJAX argument order.
- Navigation module toolbar no longer renders in preview iframe (#3456791) —
Removes page_top['navigation'] and page_top['top_bar'] elements injected by
core's Navigation module, with CSS fallback for cached pages.
- Eliminated spurious "Leave preview?" dialogs (#3393916) — Removed the
inherited node/drupal.node.preview library whose click.preview handler
intercepted all link clicks in the edit form (entity browser, reference
fields, etc.).
- Null guard in toggleVisibility (#3578231) — Prevents TypeError when Gin
Theme 5.x restructures the admin toolbar DOM.
- Config schema for node type third-party settings (#3501910) — Adds the
missing schema block for the active boolean, fixing strict config validation
on Drupal 11. Includes hook_update_N to re-save existing config.

New Features

- SDC buttons as FormElement plugins (#3365415) — SettingsButton,
NewWindowButton, and FullscreenButton are now proper #[FormElement] plugins in
src/Element/, making them alterable via hook_form_alter().
- Tugboat support (#3508471) — Added .tugboat/config.yml for automated preview
environments.

Maintenance

- PHPUnit 11 compatibility — Added ^11.0 constraint so the test suite runs on
Drupal 11.3's shipped PHPUnit version.
- PHPStan baseline — Generated baseline for Prophecy/ObjectProphecy test-only
errors; src/ remains fully guarded.
- Drupal 11.3 preparation — General compatibility updates.