Add opt-in configuration overrides

integrations/ckconfig/contracts.go

@@ -15,6 +15,8 @@ type Selection struct {
 	Config commandkit.Supplied[string]
 	// Overlay is the caller-supplied overlay path, if present.
 	Overlay commandkit.Supplied[string]
+	// Overrides contains ordered CLI override records, or nil when none were supplied.
+	Overrides []configkit.Override
 }
 
 // Operation identifies a supported standard configuration operation.