Refactor: load execution profiles from YAML and split prompt definitions into promptdef repository

internal/promptdef/testdata/no_templates.yaml

@@ -0,0 +1,9 @@
+id: no-templates
+version: 1.0.0
+inputs:
+  - name: transcript
+    required: true
+templates: []
+output_format: text
+validation:
+  validation_mode: none