Clarify collection contracts and migration docs

engine.go

@@ -248,7 +248,9 @@ func NewEngine(cfg Config, opts ...Option) (*Engine, error) {
 // execution work.
 //
 // InspectPrompt requires a nonblank promptID and performs an exact,
-// case-sensitive lookup in the captured configuration snapshot.
+// case-sensitive lookup in the captured configuration snapshot. A
+// namespace-scoped view qualifies slashless caller IDs before lookup; already
+// qualified IDs pass through. Prompt version labels do not select definitions.
 //
 // A successful result proves that the selected definition and any referenced
 // message content files were structurally loaded. Inputs are returned in