refactor(genui): have CatalogItem implement core.ComponentApi

[andrewkolos]

Towards #811.

Implements suggestion made in #974 (comment)

[gemini-code-assist]

Code Review

This pull request simplifies the codebase by having CatalogItem directly implement core.ComponentApi instead of using an intermediate wrapper class (_CatalogItemComponentApi). This allows coreCatalogFor to directly map catalog.items to the components list. A test was also added to verify this implementation. The reviewer suggested explicitly casting the list of items to core.ComponentApi to prevent potential runtime type errors due to covariance.

[gemini-code-assist]

While List<CatalogItem> is covariant and can be assigned to List<core.ComponentApi>, it is safer and more idiomatic to explicitly cast the iterable to ensure the runtime type of the list matches the expected List<core.ComponentApi>. This prevents potential runtime type errors if the receiving class performs operations that expect a List<core.ComponentApi> rather than a List<CatalogItem>.

Suggested change

	components: catalog.items.toList(growable: false),
	components: catalog.items.cast<core.ComponentApi>().toList(growable: false),

[github-actions]

Package publishing

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Package	Version	Status	Publish tag (post-merge)
package:a2ui_core	0.0.1-wip002	ready to publish	a2ui_core-v0.0.1-wip002
package:genai_primitives	0.2.4	ready to publish	genai_primitives-v0.2.4
package:genui	0.9.2	(error) pubspec version (0.9.2) and changelog (0.10.0) don't agree
package:genui_a2a	0.9.0	(error) pubspec version (0.9.0) and changelog (0.10.0) don't agree
package:json_schema_builder	0.1.5	already published at pub.dev

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