Consolidate public JSON serialization

internal/domain/domain.go

@@ -97,22 +97,22 @@ type RunResult struct {
 // PreparedRun contains pre-LLM execution state from the prepare/render phase.
 // It must never include resolved API key values, model output, or validation data.
 type PreparedRun struct {
-	PromptID             string                  `json:"prompt_id"`
-	PromptVersion        string                  `json:"prompt_version,omitempty"`
-	PromptHash           string                  `json:"prompt_hash,omitempty"`
-	SelectedProfileID    string                  `json:"selected_profile_id"`
-	SelectedBackendID    string                  `json:"selected_backend_id,omitempty"`
-	EffectiveModelParams ExecutionTarget         `json:"effective_model_params"`
-	TargetPresence       ExecutionTargetPresence `json:"-"`
-	OutputContract       OutputContract          `json:"output_contract"`
-	StructuredOutput     *StructuredOutputSpec   `json:"structured_output,omitempty"`
-	InputHashes          map[string]string       `json:"input_hashes,omitempty"`
-	SessionID            string                  `json:"session_id,omitempty"`
-	RenderedPromptHash   string                  `json:"rendered_prompt_hash"`
-	Messages             []RenderedMessage       `json:"messages"`
-	StartTime            time.Time               `json:"start_time,omitempty"`
-	EndTime              time.Time               `json:"end_time,omitempty"`
-	DurationMS           int64                   `json:"duration_ms,omitempty"`
+	PromptID             string
+	PromptVersion        string
+	PromptHash           string
+	SelectedProfileID    string
+	SelectedBackendID    string
+	EffectiveModelParams ExecutionTarget
+	TargetPresence       ExecutionTargetPresence
+	OutputContract       OutputContract
+	StructuredOutput     *StructuredOutputSpec
+	InputHashes          map[string]string
+	SessionID            string
+	RenderedPromptHash   string
+	Messages             []RenderedMessage
+	StartTime            time.Time
+	EndTime              time.Time
+	DurationMS           int64
 }
 
 // ArtifactRef represents a reference to an input artifact.