Finalize import discovery documentation and audits

lifecycle.go

@@ -78,7 +78,8 @@ const (
 // in effect: Required false, Follow true, Hidden true, and Recursive false.
 // Pattern applies to directory searches; nil leaves filenames unrestricted,
 // while a non-nil empty slice selects none. Defaults apply to main, underlay,
-// and transitive imports, not selected overlays.
+// and transitive imports, not selected overlays. Load calls snapshot the
+// pointed-to booleans and Pattern slice before acquiring sources.
 type ImportDefaults struct {
 	// Required defaults absence handling. For path, true requires every named
 	// file; for dir and glob, true requires at least one selected file.