Require AI Disclosure 1.0.0-beta1 or later

Generated with the help of an LLM.

Problem/Motivation

This module requires drupal/ai_disclosure: ^1.0.0-alpha3, the first release with GradeLookupInterface. Since then AI Disclosure has released 1.0.0-beta1 (12 October) and 1.0.0-beta2 (28 October), and the README already recommends beta1 or later. The floor still admits alpha3, and two of the current known issues exist only because of that:

• On alpha3, every trusted upload sets a suggestion an editor has already accepted or dismissed back to pending, even when the new file reads the same. From beta1 the decision is kept.
• alpha3 declares its config entities with @EntityType annotations only, which Drupal 13 removes. beta1 adds the #[ConfigEntityType] attribute.

A beta of this module should not rest on an alpha of its one required module. And the floor is easier to raise before this module's beta than after it.

Proposed resolution

• composer.json: "drupal/ai_disclosure": "^1.0.0-beta1", pinned by a unit test.
• The install-time requirement message names drupal/ai_disclosure:^1.0.0-beta1, and its test asserts that line.
• The kernel test that expects a different outcome on alpha3 keeps only the beta behaviour: a decided suggestion stays decided.
• README and CHANGELOG: the new floor, the update command for a site on alpha3, and the two known issues above removed.

Nothing else in the code changes, and no API that only a beta has is used.

Remaining tasks

• Failing tests, then the change.
• Measure on real sites: Composer refuses alpha3 with this branch; what composer update drupal/content_credentials alone does on an alpha3 site, and that updating both packages plus drush updatedb brings it up (including any update hooks of AI Disclosure); the whole suite on exactly beta1 and on beta2. CI installs only the newest release, so the floor itself is run by hand.

Out of scope

• Raising the floor to beta2.
• Raising the core or PHP floor.