Migrate Resource Group (Scaling Group) scope ownership data to the Virtual Scope model

Migrate existing Resource Group (Scaling Group) scope ownership rows in association_scopes_entities into the Virtual Scope chain: backfill virtual_scopes rows for existing Resource Group (Scaling Group) owners, a self scope_binding per owner VS, scope_bindings for existing scope->Resource Group (Scaling Group) links, and entity_memberships for existing Resource Group (Scaling Group)->child ownership. Verify no ownership/permission regressions after migration.

[Aligned to BEP-1062 (#12842): correct table names are virtual_scopes / scope_bindings / entity_memberships (previously scope_virtual / virtual_entity, which do not exist in code). Resolution is non-recursive; ownership resolves via the self scope_binding.]

JIRA Issue: BA-6665

Start by tracing the existing association_scopes_entities ownership data and the schema or migration definitions for virtual_scopes, scope_bindings, and entity_memberships. Verify that the backfill creates the specified self and link bindings and child memberships, then check that ownership and permissions remain unchanged after migration.

Written by the indexing model from the issue text.