Add profile inheritance definition support

types.go

@@ -458,6 +458,12 @@ type ExecutionTargetOverride struct {
 type Profile struct {
 	// ID is the required non-blank profile identifier. WithProfiles trims it.
 	ID string
+	// BaseProfileID optionally names one base profile. WithProfiles trims it. A
+	// non-blank value permits required target fields to be inherited when the
+	// profile is selected or inspected, which is also when reference existence
+	// and resolved completeness are checked. A blank value leaves this as a
+	// standalone profile.
+	BaseProfileID string
 	// BackendID optionally selects an engine backend. WithProfiles trims it.
 	// Backend membership is checked when a request selects the profile; an
 	// unknown ID makes preparation fail with ErrProfileLoad.
@@ -506,6 +512,8 @@ type Profile struct {
 type OpenAICompatibleProfileConfig struct {
 	// ID becomes Profile.ID.
 	ID string
+	// BaseProfileID becomes Profile.BaseProfileID.
+	BaseProfileID string
 	// BackendID becomes Profile.BackendID.
 	BackendID string
 	// Endpoint becomes Profile.Endpoint.