Initial rebrand: @polkadot -> @pezkuwi (14 packages)

- Package namespace: @polkadot/* -> @pezkuwi/*
- Repository: polkadot-js/common -> pezkuwichain/pezkuwi-common
- Author: Pezkuwi Team <team@pezkuwichain.io>

Core packages:
- @pezkuwi/util (utilities)
- @pezkuwi/util-crypto (crypto primitives)
- @pezkuwi/keyring (account management)
- @pezkuwi/networks (chain metadata)
- @pezkuwi/hw-ledger (Ledger hardware wallet)
- @pezkuwi/x-* (10 polyfill packages)

Total: 14 packages
Upstream: polkadot-js/common v14.0.1

packages/util/src/assert.ts

@@ -0,0 +1,50 @@
+// Copyright 2017-2025 @polkadot/util authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import { isFunction } from './is/function.js';
+
+type MessageFn = () => string;
+
+/**
+ * @name assert
+ * @summary Checks for a valid test, if not Error is thrown.
+ * @description
+ * Checks that `test` is a truthy value. If value is falsy (`null`, `undefined`, `false`, ...), it throws an Error with the supplied `message`. When `test` passes, `true` is returned.
+ * @example
+ * <BR>
+ *
+ * ```javascript
+ * const { assert } from '@pezkuwi/util';
+ *
+ * assert(true, 'True should be true'); // passes
+ * assert(false, 'False should not be true'); // Error thrown
+ * assert(false, () => 'message'); // Error with 'message'
+ * ```
+ */
+export function assert (condition: unknown, message: string | MessageFn): asserts condition {
+  if (!condition) {
+    throw new Error(
+      isFunction(message)
+        ? message()
+        : message
+    );
+  }
+}
+
+/**
+ * @name assertReturn
+ * @description Returns when the value is not undefined/null, otherwise throws assertion error
+ */
+export function assertReturn <T> (value: T | undefined | null, message: string | MessageFn): T {
+  assert(value !== undefined && value !== null, message);
+
+  return value;
+}
+
+/**
+ * @name assertUnreachable
+ * @description An assertion helper that ensures all codepaths are followed
+ */
+export function assertUnreachable (x: never): never {
+  throw new Error(`This codepath should be unreachable. Unhandled input: ${x as unknown as string}`);
+}