Add Shiden chain

[Zhangnong]

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PR-Codex overview

This PR introduces the Shiden blockchain to the project by adding its definition and exporting it for use in the application.

Detailed summary

• Added a new entry for Shiden in the src/chains/index.ts file.
• Created a new file src/chains/definitions/shiden.ts with the shiden chain definition, including:
  • id: 336
  • name: 'Shiden'
  • nativeCurrency: details for SDN
  • rpcUrls: default HTTP and WebSocket endpoints
  • blockExplorers: default explorer details
  • testnet: set to false

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🦋 Changeset detected

Latest commit: b6ea9e6

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

This PR includes changesets to release 1 package

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viem	Patch

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