Summary

Phase 2 of the scoped secret store implementation (#4192).

Add factory convenience helpers so callers construct wrappers consistently without needing to know the layering order.

Work

• CreateUserSecretProvider(providerType) (secrets.Provider, error) in factory.go — wraps CreateSecretProvider result in UserProvider
• CreateScopedSecretProvider(providerType, scope string) (secrets.Provider, error) in factory.go — wraps CreateSecretProvider result in ScopedProvider

Dependencies

Depends on Phase 1 (#4192).