feat: @egos/hacash-sdk — TypeScript SDK for Hacash RPC

[enioxt]

Problem

Developers in the Hacash community struggle with the RPC API:

• Miran: "How can I send a signed transaction to the network automatically from my website?"
• No npm package exists for Hacash RPC
• Raw HTTP calls with no types or error handling

Proposal

Publish @egos/hacash-sdk to npm.

What we already have

apps/egos-web/src/services/hacash.ts — 113 lines of typed API client covering: latest, supply, hashrate, block, transaction, balance, diamond, feeAverage. This is ~60% of the SDK.

Features

• All RPC endpoints typed (query/latest, query/supply, query/hashrate, query/block, etc.)
• Transaction construction helpers
• HACD name validation + number ↔ name utilities
• Proper error handling + retry logic
• Works in Node.js and browser
• Published to npm

RPC API Reference

https://github.com/hacash/paper/blob/master/service/rpc_api_doc.md

PRD: docs/plans/HACASH_COMMUNITY_TOOLS_PRD.md — Project 4