feat: add heco chain

[pk-850]

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PR-Codex overview

This PR introduces support for the Heco chain in the codebase, enhancing the existing chain definitions.

Detailed summary

• Added a new entry for heco in src/chains/index.ts.
• Created heco.ts in src/chains/definitions/ with:
  • Chain ID: 128
  • Name: 'Huobi ECO Chain Mainnet'
  • Native currency: HT (symbol: HT, decimals: 18)
  • RPC URLs for mainnet
  • Block explorer details for Heco Scan
  • Marked as not a testnet.

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🦋 Changeset detected

Latest commit: c995183

The changes in this PR will be included in the next version bump.

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[jxom]

Please reopen the PR once comment is addressed.