Feature: Polkadot Staking Integration Example (bond/nominate process)

[alireza237237]

💡 Idea
Add a comprehensive Polkadot staking integration script example to func-js documentation or as a sample utility, demonstrating all key steps: bonding, nomination, signing/extrinsic management, unified API usage, and error handling, as shown below:

import { readFileSync } from 'fs';
import { ApiPromise, WsProvider, Keyring } from '@polkadot/api';
import '@polkadot/api-augment';
import axios from 'axios';
// ... full code omitted for brevity ...

🤔 Motivation
Many TON/Func-js developers need robust cross-chain staking solutions and a reference for integrating Polkadot staking within JavaScript environments. Sharing such an example will help with similar implementations and debugging external integration flows.

📝 Details

• Example covers loading keystore, bonding, nomination, signing, broadcasting, and error handling
• Utilizes Polkadot JS api and Unfied API
• Handles keystore decryption, extrinsic creation/signing, broadcast
• Provides structure for modular external API calls
• Includes clear logging and error handling best practices

Is your feature request related to a problem? Please describe.
Finding reliable and up-to-date Polkadot staking JavaScript integration references is difficult. Many existing solutions are incomplete or lack proper error coverage.

Describe the solution you'd like
Add an official, self-contained Polkadot staking script reference in func-js docs, utilities, or examples, with implementation explainers and commentary.

Describe alternatives you've considered

• Direct integration with Polkadot.js APIs only
• Using separate REST endpoints/scripts for transaction building/broadcast
• Relying on external documentation/examples

Additional context
Script provided above includes logic for both bonding and nomination in Polkadot via unified API and local keystore.