Publish effective LLM backend provenance

internal/modules/generic/output/json/encoder_test.go

@@ -449,6 +449,46 @@ func TestEncodePrettyPrintsJSON(t *testing.T) {
 	}
 }
 
+func TestEncodePublishesLLMProfileProvenance(t *testing.T) {
+	result, err := New().Encode(context.Background(), contracts.OutputRequest{
+		Manifest: artifacts.RunManifest{
+			RunID: "run-1",
+			LLMProfiles: []artifacts.LLMProfileManifest{
+				{
+					ID:              "endpoint-profile",
+					Provider:        "promptkit",
+					Model:           "endpoint-model",
+					ReasoningEffort: "low",
+				},
+				{
+					ID:              "profile",
+					Provider:        "promptkit",
+					Model:           "model",
+					BackendID:       "openrouter",
+					ReasoningEffort: "high",
+				},
+			},
+		},
+	})
+	if err != nil {
+		t.Fatalf("Encode() error = %v, want nil", err)
+	}
+
+	manifest := decodeObject(t, fileBytes(t, result.Files, "manifest.json"))
+	profiles := manifest["llm_profiles"].([]any)
+	if len(profiles) != 2 {
+		t.Fatalf("llm_profiles = %#v, want two entries", profiles)
+	}
+	endpointProfile := profiles[0].(map[string]any)
+	if _, exists := endpointProfile["backend_id"]; exists || endpointProfile["reasoning_effort"] != "low" {
+		t.Fatalf("endpoint-only LLM profile = %#v, want omitted backend and published reasoning", endpointProfile)
+	}
+	backendProfile := profiles[1].(map[string]any)
+	if backendProfile["backend_id"] != "openrouter" || backendProfile["reasoning_effort"] != "high" {
+		t.Fatalf("backend LLM profile = %#v, want published backend and reasoning fields", backendProfile)
+	}
+}
+
 func TestEncodeIncludesManifestReferences(t *testing.T) {
 	result, err := New().Encode(context.Background(), contracts.OutputRequest{
 		Manifest: artifacts.RunManifest{