Carry optional prompt labels through results

internal/domain/domain.go

@@ -80,7 +80,7 @@ type RunResult struct {
 	RawOutput            string
 	Validation           ValidationResult
 	PromptID             string
-	PromptVersion        string
+	PromptVersion        *string
 	PromptHash           string
 	SessionID            string
 	RenderedPromptHash   string
@@ -100,7 +100,7 @@ type RunResult struct {
 // It must never include resolved API key values, model output, or validation data.
 type PreparedRun struct {
 	PromptID             string
-	PromptVersion        string
+	PromptVersion        *string
 	PromptHash           string
 	SelectedProfileID    string
 	SelectedBackendID    string
@@ -137,13 +137,13 @@ type Artifact struct {
 // PromptIdentity identifies one configured prompt and its descriptive version label.
 type PromptIdentity struct {
 	ID      string
-	Version string
+	Version *string
 }
 
 // PromptDefinition represents a configured prompt execution definition.
 type PromptDefinition struct {
 	ID             string                  `yaml:"id"`
-	Version        string                  `yaml:"version"`
+	Version        *string                 `yaml:"version"`
 	DefaultProfile string                  `yaml:"default_profile"`
 	Description    string                  `yaml:"description"`
 	SessionID      string                  `yaml:"session_id" json:"session_id,omitempty"`
@@ -156,7 +156,7 @@ type PromptDefinition struct {
 // PromptInspection is the resolved result of exact prompt inspection.
 type PromptInspection struct {
 	PromptID         string
-	PromptVersion    string
+	PromptVersion    *string
 	PromptHash       string
 	DefaultProfileID string
 	Inputs           []PromptInput