Add Pezkuwi SDK UI - Polkadot.js Apps clone

- Clone Polkadot.js Apps repository
- Update package.json with Pezkuwi branding
- Add Pezkuwi endpoint to production chains (wss://pezkuwichain.app:9944)
- Create comprehensive README for SDK UI
- Set up project structure with all packages

Next steps:
- Apply Kurdistan colors (Kesk, Sor, Zer, Spi + Black) to UI theme
- Replace logos with Pezkuwi branding
- Test build and deployment

pezkuwi-sdk-ui/packages/react-hooks/src/useFormField.ts

@@ -0,0 +1,31 @@
+// Copyright 2017-2025 @polkadot/react-hooks authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import { useCallback, useMemo, useState } from 'react';
+
+import { isUndefined } from '@polkadot/util';
+
+export type FormField<T> = [
+  T | null,
+  boolean,
+  (_?: T | null) => void
+];
+
+type ValidateFn<T> = (_: T) => boolean;
+
+const defaultValidate = (): boolean => true;
+
+// FIXME Since we use generics, this cannot be a createNamedHook as of yet
+export function useFormField<T> (defaultValue: T | null, validate: ValidateFn<T> = defaultValidate): FormField<T> {
+  const [value, setValue] = useState<T | null>(defaultValue);
+  const isValid = useMemo(
+    () => !!value && validate(value),
+    [validate, value]
+  );
+  const setter = useCallback(
+    (value?: T | null) => !isUndefined(value) && setValue(value),
+    []
+  );
+
+  return [value, isValid, setter];
+}