No config schema for bee's node-type third_party_settings — node type config fails validation

Problem/Motivation

BEE writes its per-bundle settings into a node type's third-party settings (bee.module, bee_node_type_edit_form_submit()):

$node_type->setThirdPartySetting('bee', 'bee', $bee_settings)->save();

…but the module ships no config schema at all — there is no config/schema/*.schema.yml anywhere in the project (confirmed at HEAD; config/install exists, config/schema does not). Nothing declares node.type.*.third_party.bee.

Consequences on a site with a BEE-enabled bundle:

1. The node type's config object fails validation. $node_type->getTypedData()->validate() returns 12 violations. Because the third-party key has no schema, typed config falls back to the node type's own definition, producing not just 'bee' is not a supported key but a cascade of nonsense demands — 'uuid' is a required key, 'name' is a required key, 'type' is a required key — inside third_party_settings.bee:
   

    [third_party_settings.bee.bee]  'bee' is not a supported key.
    [third_party_settings.bee]      'uuid' is a required key.
    [third_party_settings.bee]      'langcode' is a required key.
    [third_party_settings.bee]      'status' is a required key.
    [third_party_settings.bee]      'dependencies' is a required key.
    [third_party_settings.bee]      'name' is a required key.
    [third_party_settings.bee]      'type' is a required key.
    [third_party_settings.bee]      'description' is a required key.
    [third_party_settings.bee]      'help' is a required key.

2. Real interop breakage. On Drupal CMS, the content_template_disable_preview ECA rule errors on every Canvas ContentTemplate save for a BEE-enabled bundle, because it validates the node type. Worse, the rule's preview_mode write still lands despite the reported validation failure — so the failure is misleading as well as noisy.
3. Schema is required for correct typed-config handling generally (translation, validation, config:inspect), and Drupal is progressively enforcing full validatability of config entities.

Steps to reproduce

1. Install BEE, enable bookability on a content type (any bookable_type), save.
2. Run \Drupal::entityTypeManager()->getStorage('node_type')->load('<bundle>')->getTypedData()->validate() — 12 violations as above.
3. On Drupal CMS with Canvas: create a ContentTemplate for that bundle and save — the ECA rule errors.

Proposed resolution

Add config/schema/bee.schema.yml declaring the third-party settings BEE actually writes (keys observed on a live site: bookable, bookable_type, availability, payment, payment_default_value, type_id):

 node.type.*.third_party.bee:
   type: mapping
   label: 'BEE settings'
   mapping:
     bookable:
       type: boolean
       label: 'Bookable'
     bookable_type:
       type: string
       label: 'Bookable type (hourly or daily)'
     availability:
       type: string
       label: 'Availability'
     payment:
       type: boolean
       label: 'Payment enabled'
     payment_default_value:
       type: string
       label: 'Default payment value'
     type_id:
       type: string
       label: 'BAT unit type id'

(Maintainers should confirm the exact types/keys against the form — the above is derived from a live install.)

Remaining tasks

Confirm key list and types; add schema; ideally add a SchemaCheckTestTrait-based test so it can't regress.

User interface changes

None

API changes

None

Data model changes

None

Sponsorship

None