Specialized elements

Problem/Motivation

Part 8 of splitting #3595219: 3.0 Exploration. This issue adds support for a set of standalone, special-purpose element types that are each self-contained and don't fit the options/numeric/date families:

• likert — a question/answer matrix (questions, answers, optional N/A).
• webform_terms_of_service — terms acceptance with a link/modal.
• webform_message — an informational message element.
• webform_same — a "same as" toggle that copies another composite's values.
• webform_computed_token / webform_computed_twig — computed values.
• view — an embedded Views display.
• webform_email_confirm — an e-mail with confirmation field.

None of these are exposed in 3.x today.

Proposed resolution

Add each element type to the schema (generated type + resolvers), with the enums and producers each needs:

• likert: webform_element_likert_items and webform_element_likert_na_answer producers; WebformLikertDescriptionDisplay enum.
• terms_of_service: WebformTermsType and WebformLinkTarget enums.
• message: reuses the WebformMessageType enum.
• same: expose its fields and handle submission (WebformSubmit.php).
• computed: WebformComputedMode enum.
• view: expose the embedded view reference/display fields.
• email_confirm: expose fields (incl. required/description/help) and handle the confirmation submission.

These are largely independent of each other and could be reviewed/landed separately if preferred; they are grouped here to keep the issue count manageable. Each is small on its own.

Remaining tasks

• Add enums WebformLikertDescriptionDisplay, WebformTermsType, WebformLinkTarget, WebformComputedMode under src/Enum/; wire into WebformSchemaBuilder.php.
• Add producers WebformElementLikertItems.php, WebformElementLikertNaAnswer.php; extend WebformElementMetadata.php / WebformExtension.php for each element.
• Handle webform_same and webform_email_confirm submission in WebformSubmit.php.
• Tests: LikertTest, TermsOfServiceTest, MessageTest, SameTest + FormSubmissionSameTest, ComputedTest, ViewTest, EmailConfirmTest + FormSubmissionEmailConfirmTest, plus the matching tests/queries/*.gql fixtures and shared test-form additions.

API changes

Additive: new element types (likert, terms_of_service, message, same, computed, view, email_confirm) with their supporting enums and producers. No fields removed.

Release notes snippet

Support added for the likert, terms-of-service, message, "same as", computed, view and e-mail-confirm element types, including submission handling where applicable.