fix(BA-6025): add ON DELETE RESTRICT FK on images.registry_id

[fregataa]

Summary

• Add a real DB-level foreign key from images.registry_id to container_registries.id with ON DELETE RESTRICT. Previously only an ORM-level foreign() join existed, so deleting a registry left dangling references that the sokovan scheduler later surfaced as a misleading "Image not found in database" error during session launch.
• ON DELETE RESTRICT (over CASCADE) preserves audit traceability on kernels and deployment_revisions (whose image FKs use SET NULL) and forces operators to clear or purge images via the existing clear_images / admin_purge flows before removing a registry.
• The migration hard-deletes any pre-existing dangling image rows before creating the constraint, since the column is NOT NULL and a sentinel reassignment would mask the original deletion intent.
• Affected test fixtures using with_tables now include ContainerRegistryRow, and the two test_image fixtures in deployment tests seed a real container_registry row instead of fabricating a random registry_id.

Test plan

• pants test for all with_tables-based image tests (~46 files) passes locally.
• alembic upgrade head and round-trip downgrade -1 → upgrade head succeed on local DB.
• CI green.
• Manual: attempt to delete a registry that still has images via REST v2 — expect HTTP 409 ForeignKeyViolationError. (Follow-up ticket recommended to convert this into a domain-specific 400 with a clearer message.)

Resolves BA-6025

[Copilot]

Pull request overview

This PR adds a real database-level foreign key from images.registry_id to container_registries.id with ON DELETE RESTRICT, preventing dangling image registry references and aligning test fixtures with the new constraint.

Changes:

• Adds the ImageRow.registry_id FK and an Alembic migration to clean dangling rows before constraint creation.
• Updates many with_tables fixtures to include ContainerRegistryRow before ImageRow.
• Seeds real container registry rows in deployment-related image fixtures.

Reviewed changes

Copilot reviewed 49 out of 49 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/ai/backend/manager/models/image/row.py	Adds FK constraint on images.registry_id.
src/ai/backend/manager/models/alembic/versions/045b0e0e4384_add_fk_from_images_registry_id_to_.py	Adds migration to delete dangling images and create/drop the FK.
tests/unit/manager/test_query_userinfo.py	Adds registry table to image-related fixture tables.
tests/unit/manager/repositories/vfolder/test_vfolder_repository.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/user/test_user_repository.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/user_resource_policy/test_user_resource_policy_repository.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/test_utils.py	Adds registry table to shared repository fixture setup.
tests/unit/manager/repositories/scheduling_history/test_scheduling_history_repository.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/scheduler/test_termination.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/scheduler/test_session_network_propagation.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/scaling_group/test_scaling_group_repository.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/resource_usage_history/test_usage_bucket_entries.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/resource_usage_history/test_resource_usage_history_repository.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/resource_preset/test_resource_preset_cache_invalidation.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/resource_preset/test_check_presets.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/project_resource_policy/test_project_resource_policy.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/permission_controller/test_user_scope_sync.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/permission_controller/test_search_scopes.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/permission_controller/test_role_invitation.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/permission_controller/test_role_assignment.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/notification/test_notification_repository.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/notification/test_notification_options.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/model_card/test_model_card_search_in_project.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/model_card/test_model_card_scan.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/model_card/test_model_card_delete.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/model_card/test_model_card_creator.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/keypair_resource_policy/test_keypair_resource_policy.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/group/test_unassign_users_from_project.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/group/test_group_repository.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/group/test_group_db_source.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/group/test_assign_users_to_project.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/fair_share/test_fair_share_repository.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/error_log/test_error_log_repository.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/domain/test_domain_repository.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/auth/test_auth_repository.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/artifact/test_artifact_repository.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/artifact_revision/test_artifact_revision_repository.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/app_config/test_app_config.py	Adds registry table to fixture setup.
tests/unit/manager/repositories/agent/test_repository.py	Adds registry table to fixture setup.
tests/unit/manager/models/user/test_conditions.py	Adds registry table to fixture setup.
tests/unit/manager/models/test_vfolder_quota_scope.py	Adds registry table to fixture setup.
tests/unit/manager/models/test_vfolder_prepare_mounts.py	Adds registry table to fixture setup.
tests/unit/manager/models/test_session.py	Adds registry table to fixture setup.
tests/unit/manager/models/test_deployment_revision.py	Adds registry table and seeds a matching registry for test images.
tests/unit/manager/models/test_deployment_auto_scaling_policy.py	Adds registry table and seeds a matching registry for test images.
tests/unit/manager/models/scaling_group/test_conditions.py	Adds registry table to fixture setup.
tests/unit/manager/models/group/test_conditions.py	Adds registry table to fixture setup.
tests/unit/manager/models/domain/test_conditions.py	Adds registry table to fixture setup.

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[seedspirit]

It is better to reflect Copilot's review

[jopemachine]

Could you check what error is raised when the container registry delete mutation fails due to existing image rows? Also, it would be good to add a note to the delete mutation description indicating that this error can occur when image rows still exist.