Light-DOM element built on createSqlEditor(): form participation via
ElementInternals (name= field, reset support), schema fetched from
{base-url}/{database}/-/editor-schema.json or schema-url= without ever
blocking editing, cancelable submit event on Mod/Shift-Enter driving
form.requestSubmit(), readOnly/value/schema/view properties, format()
via the sql-formatter global, theming through CSS custom properties
with appearance-preserving fallbacks. Auto-registers the tag on import
(guarded). Manual-QA page at demos/sql-editor-element.html.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
