feat(BA-3704): apply RBAC Creator pattern to Artifact Registry

[fregataa]

Summary

• Add ArtifactRegistryCreatorSpec(CreatorSpec[ArtifactRegistryRow]) with fields: name, registry_id, type
• Add create_artifact_registry() method to ArtifactRegistryDBSource using RBACEntityCreator + execute_rbac_entity_creator
• Add corresponding create_artifact_registry() method to ArtifactRegistryRepository with resilience policy

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR applies the RBAC Creator pattern to the Artifact Registry domain and introduces a new batch creation utility for entities with per-entity scope references.

Changes:

• Added execute_rbac_entity_creators() function to support batch creation of multiple entities where each can have its own primary and additional scope references (unlike execute_rbac_bulk_entity_creator which shares a single scope)
• Fixed error messages in entity creator functions from "Purger only supports..." to "Entity creator only supports..."
• Added ArtifactRegistryCreatorSpec implementing the CreatorSpec pattern for artifact registries
• Added create_artifact_registry() methods to both ArtifactRegistryRepository and ArtifactRegistryDBSource using the RBAC entity creator pattern
• Refactored test file to use fixtures for better test organization and added comprehensive tests for the new batch creator function

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/ai/backend/manager/repositories/base/rbac/entity_creator.py	Added new execute_rbac_entity_creators() function for batch creation with per-entity scopes; corrected error messages from "Purger" to "Entity creator"
tests/unit/manager/repositories/base/rbac/test_entity_creator.py	Refactored tests to use fixtures; added comprehensive test coverage for execute_rbac_entity_creators including empty list, same scope, different scopes, and additional scopes scenarios; added composite PK rejection tests
src/ai/backend/manager/repositories/artifact_registry/creators.py	New file defining ArtifactRegistryCreatorSpec following the CreatorSpec pattern
src/ai/backend/manager/repositories/artifact_registry/repository.py	Added create_artifact_registry() method with resilience policy
src/ai/backend/manager/repositories/artifact_registry/db_source/db_source.py	Added create_artifact_registry() method using execute_rbac_entity_creator
changes/9255.enhance.md	Added changelog entry for the new batch creator function

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[fregataa]

Changed to draft since Artifact Registries can be mapped to domain/project N:N