fix: resolve onError type conflict in PromptInputProps (#132)

Exclude "onError" from HTMLAttributes<HTMLFormElement> to prevent conflict
with the custom onError callback that provides specific file upload error
codes ("max_files", "max_file_size", "accept").

Author: rexdotsh

packages/elements/src/prompt-input.tsx

@@ -418,7 +418,7 @@ export type PromptInputMessage = {
 
 export type PromptInputProps = Omit<
   HTMLAttributes<HTMLFormElement>,
-  "onSubmit"
+  "onSubmit" | "onError"
 > & {
   accept?: string; // e.g., "image/*" or leave undefined for any
   multiple?: boolean;