Replace endpoint/deployment ORM relationship usages with explicit queries and remove them

Replace remaining usages of EndpointRow relationships (current_revision_row, deploying_revision_row, deployment_policy, routings, session_owner_row, created_user_row, tokens, primary/target_replica_group_row), DeploymentRevisionRow (image_row, runtime_variant_row, resource_slot_rows), RoutingRow (endpoint_row, session_row), and EndpointAutoScalingRuleRow.endpoint_row with explicit queries via the repository/ops layer, then remove the relationship() definitions and dependent loader options.

JIRA Issue: BA-7227

Locate the EndpointRow, DeploymentRevisionRow, RoutingRow, and EndpointAutoScalingRuleRow relationship usages, then trace the repository/ops layer paths that replace them with explicit queries. Done means the listed relationships and dependent loader options are removed, with all remaining usages migrated to those queries.

Written by the indexing model from the issue text.