Support predicate callbacks in fake index assertions

[stevebauman]

What changed

• Allow fake index creation assertions to match an index by name without requiring an exact IndexBlueprint.
• Support optional predicate callbacks that inspect the recorded blueprint, mapping, or settings.
• Preserve exact IndexBlueprint, Mapping, and Settings assertions for backward compatibility.
• Add coverage for successful name-only assertions, successful predicates, missing operations, and predicates that return false.

Why

The fake previously treated expected mapping and settings objects as exact operation definitions. This made higher-level assertions fail when an index was created with mapping or settings data that the assertion did not explicitly rebuild. Assertion callbacks should inspect the operation that was actually recorded, following the same predicate semantics used by Laravel's fakes.

Developer impact

Consumers can now assert only that an operation occurred:

$index->assertCreated('users');
$index->assertMappingPut('users');
$index->assertSettingsPut('users');

They can optionally add a predicate when the recorded definition matters, while existing exact-object assertions continue to work.