Flip around HiddenInput's 'valid' prop into 'invalid' and make it optional

Author: jviide

.changeset/weak-walls-attend.md

@@ -0,0 +1,5 @@
+---
+"@badrap/libapp": patch
+---
+
+Flip around HiddenInput's 'valid' prop into 'invalid' and make it optional

src/ui/experimental/HiddenInput.ts

@@ -3,7 +3,7 @@ import { Json, UiNode, element } from "../internal.js";
 type HiddenInputProps = {
   name: string;
   value?: Json;
-  valid: boolean;
+  invalid?: boolean;
 };
 
 export function HiddenInput(props: HiddenInputProps): UiNode {