Build presence-aware execution targets from effective configuration

internal/domain/domain.go

@@ -208,6 +208,10 @@ type ExecutionProfile struct {
 	APIKeyEnv       string         `yaml:"api_key_env"`
 	APIKeyRequired  bool           `yaml:"-" json:"-"`
 	ExtraParams     map[string]any `yaml:"extra_params"`
+	// ResolvedTarget is an execution-owned snapshot assembled from effective
+	// configuration and backend defaults. Legacy source repositories leave it nil.
+	ResolvedTarget *ExecutionTarget        `yaml:"-" json:"-"`
+	TargetPresence ExecutionTargetPresence `yaml:"-" json:"-"`
 }
 
 // ExecutionTargetOverride represents per-request runtime setting overrides.
@@ -224,8 +228,9 @@ type ExecutionTargetOverride struct {
 	ExtraParams     map[string]any `json:"extra_params,omitempty"`
 }
 
-// ExecutionTargetPresence tracks which effective runtime fields came from an
-// explicit request override even when the resolved value is a zero value.
+// ExecutionTargetPresence tracks effective numeric values that must be sent
+// even when they are zero. Values may come from configuration or a request
+// override; explicit configuration null suppresses the corresponding bit.
 type ExecutionTargetPresence struct {
 	Temperature    bool
 	MaxTokens      bool