Add the missing core widgets

[sneridagh]

Step 7 of #243: the missing core widgets. Each one is built against the widget contract and runs describeWidgetContract.

Stacked on #262. Part of the review guide in #244 (comment).

Closes #243

Widgets

Widget	Registered for	Value
SelectWidget	the choices widget (choices or vocabulary), widget: 'select'	a token, or null
ArrayWidget	type: 'array', widget: 'array', widget: 'token'	a list of tokens
NumberWidget	type: 'number', type: 'integer'	a number, or null
FileWidget	factory: 'File', factory: 'Image', widget: 'file'	the file, or null
EmailWidget, PasswordWidget, UrlWidget	widget: 'email', 'password', 'url'	a string

• Select (B3). config.widgets.choices is now registered with config.registerWidget({ key: 'choices', definition: SelectWidget }). registerWidget now accepts the choices slot, which holds one widget, and tells a component from a map of widgets even when the component has a displayName (before, counting its keys made it a map). The options come from the schema's choices, or from the field's vocabulary through a new @vocabulary resource route. Optional fields get a "No value" option.
• Tokens ([CMSUI Widgets] - ArrayWidget #8). Free tokens, like the tags of a page, with suggestions from a vocabulary in widgetOptions. A closed list when items has choices or a vocabulary.
• Number. A new Quanta NumberField control. It reads minimum and maximum, and takes whole numbers only for integer.
• File (Add Image Content tab crashes because the image field is rendered as a TextField #163 follow-up). File and image fields (the Image's image, the lead image) used to get ImageWidget, which stores a URL that the content API can't save. They now get FileWidget, which uploads the file (base64) and keeps a stored file as it is. ImageWidget stays the widget of URL-valued widget: 'image' fields, such as the image block's url.
• Email, password, URL. TextField with the right input type. The validators for widget: 'email' and widget: 'url' already existed (Validate schema-driven forms #256).

Changes found along the way

• Lookup order. A widget registered for a vocabulary now wins over the choices widget. Without this, plone.app.vocabularies.Catalog fields would get a select that loads the whole catalog instead of the object browser. The guide documents the new order.
• Term objects. plone.restapi sends some choice values as {token, title} objects (language, sort_tabs_on, displayed_types). Select and array read terms and write tokens. Before, these values crashed the render as "Objects are not valid as a React child".
• @plone/client content schemas.
  • allow_discussion now accepts its choice tokens "True"/"False", which the backend accepts. Before, Zod rejected the save.
  • preview_image accepts a stored file.
  • The file fields accept null.
• getVocabulary takes a b_size (-1 returns all the terms).

Contract gap

SelectWidget skips the contract's required check, with the reason recorded in the test. React Aria's Select marks a required field with data-required and the label's marker, not with aria-required, which a button can't have.

Tests

• Contract tests: 7 new widgets, 117 passing, 1 skipped (the check above).
• Unit tests: the lookup order, and registering the choices widget with registerWidget (a component with a displayName; fails with the old key counting).
• New acceptance tests (core-widgets.test.ts). Each one fails when the old widget registrations are restored:
  • Tags are added with Enter and saved as a list.
  • The language select loads its vocabulary, and allow_discussion (stored as a boolean) is read and saved.
  • The navigation control panel shows its term lists and saves them.
  • The mail control panel saves smtp_port as a number and has a password input.
  • The File and Image add forms upload the file. This replaces the Add Image Content tab crashes because the image field is rendered as a TextField #163 add-form test.
• Updated acceptance tests: the lead image now resolves to the file widget. The Add Image Content tab crashes because the image field is rendered as a TextField #163 object browser location check now runs in the image block settings of a nested page.
• Full acceptance suite: 217/217 passed against the acceptance backend.

Docs

• Core widgets reference: a section per widget.
• Guide: the lookup order and the choices widget.
• Upgrade guide: "File and image fields store files", with alpha.20 admonitions.

[sneridagh]

LGTM, with room to improve, I guess

[pnicolli]

Maybe this should be an optional parameter?

[sneridagh]

-1 does not mean "give them all to me", no pagination? I can see the definition is optional in zod schema.

[sneridagh]

Now I get you, you were referring to the route, not the client! Implementing!