Migrate prompt fixtures to direct definitions

integrations/ckprompt/comparison_composition_test.go

@@ -225,13 +225,14 @@ func comparisonEngine(t *testing.T, greeting string) *promptkit.Engine {
 	t.Helper()
 	configuration := `prompts:
   briefing:
-    "1":
-      messages:
-        - role: user
-          content: "Hello"
-      output:
-        format: text
-        validation_mode: none
+    version: "1"
+    default_profile: default
+    messages:
+      - role: user
+        content: "Hello"
+    output:
+      format: text
+      validation_mode: none
 backends:
   local:
     endpoint: "https://example.invalid/v1"