Add Hedera support

[se7enarianelabs]

Description

This PR introduces full Hedera network support to the X402 protocol, enabling seamless payment processing using Hedera's native HBAR currency and Hedera Token Service (HTS) tokens. The integration provides a complete suite of tools for developers to implement X402 payments on the Hedera network.

Tests

Unit Test Coverage Summary

• Total Tests: 86 Hedera-specific tests across 4 test files
• Test Execution: All tests passing ✅
• Coverage Areas: RPC, Wallet, Transactions, and Client Integration

Test Suites

• Unit Tests (86 tests)
  • RPC module tests (24 tests)
  • Wallet module tests (23 tests)
  • Transaction module tests (23 tests)
  • Client integration tests (16 tests)

Manual Testing Summary

We conducted extensive manual testing across all X402 integration points to ensure Hedera support works seamlessly with existing infrastructure. The testing covered client-side implementations, server-side middleware, facilitator services, and full-stack applications.

✅ Verified Working Integrations:

1. HTTP Clients: Axios, Fetch
2. Web Servers: Express, Hono, Next.js
3. Facilitator Services: Payment settlement

Checklist

• [X] I have formatted and linted my code
• [X] All new and existing tests pass
• [X] My commits are signed (required for merge) -- you may need to rebase if you initially pushed unsigned commits

[cb-heimdall]

🟡 Heimdall Review Status

Requirement	Status	More Info
Reviews	🟡 0/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 2 if repo is sensitive 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 0 Sum 1

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[microchipgnu]

Excited for this integration!

[Ashe-Oro]

Hedera support lessgo

[kpachhai]

This is much needed. Will be amazing to see x402 type payments working on Hedera natively!!

[mgarbs]

This is desperately needed and done already? When does it go live? 🚀 🚀 🚀 🚀 Amazing work guys 👏

[EMerchant90]

Excited to see this blossom!

[prime-optimal]

Description

This PR introduces full Hedera network support to the X402 protocol, enabling seamless payment processing using Hedera's native HBAR currency and Hedera Token Service (HTS) tokens. The integration provides a complete suite of tools for developers to implement X402 payments on the Hedera network.

nice work, hedera makin early moves!