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-crypto/src/hd/ledger/derivePrivate.ts

@@ -0,0 +1,34 @@
+// Copyright 2017-2025 @polkadot/util-crypto authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import { BN_EIGHT, bnToU8a, u8aConcat, u8aToBn } from '@pezkuwi/util';
+
+import { BN_LE_32_OPTS, BN_LE_512_OPTS, BN_LE_OPTS } from '../../bn.js';
+import { hmacShaAsU8a } from '../../hmac/index.js';
+
+// performs hard-only derivation on the xprv
+export function ledgerDerivePrivate (xprv: Uint8Array, index: number): Uint8Array {
+  const kl = xprv.subarray(0, 32);
+  const kr = xprv.subarray(32, 64);
+  const cc = xprv.subarray(64, 96);
+  const data = u8aConcat([0], kl, kr, bnToU8a(index, BN_LE_32_OPTS));
+  const z = hmacShaAsU8a(cc, data, 512);
+
+  data[0] = 0x01;
+
+  return u8aConcat(
+    bnToU8a(
+      u8aToBn(kl, BN_LE_OPTS).iadd(
+        u8aToBn(z.subarray(0, 28), BN_LE_OPTS).imul(BN_EIGHT)
+      ),
+      BN_LE_512_OPTS
+    ).subarray(0, 32),
+    bnToU8a(
+      u8aToBn(kr, BN_LE_OPTS).iadd(
+        u8aToBn(z.subarray(32, 64), BN_LE_OPTS)
+      ),
+      BN_LE_512_OPTS
+    ).subarray(0, 32),
+    hmacShaAsU8a(cc, data, 512).subarray(32, 64)
+  );
+}