feat: add swan chain

[tom-jordan1]

PR-Codex overview

This PR adds support for the Swan chain to the project.

Detailed summary

• Added Swan chain to index.ts
• Defined swan chain in swan.ts with ID, name, native currency, RPC URLs, block explorers, and testnet status

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PR-Codex overview

This PR introduces the Swan Chain and related testnets to the codebase, enhancing the blockchain definitions with new networks and their configurations.

Detailed summary

• Added swan mainnet with ID 254 and RPC URL https://mainnet-rpc.swanchain.org.
• Added swanSaturnTestnet with ID 2024 and RPC URL https://saturn-rpc.swanchain.io.
• Added swanProximaTestnet with ID 20241133 and RPC URL https://rpc-proxima.swanchain.io.
• Exported new chains in src/chains/index.ts.

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[changeset-bot]

🦋 Changeset detected

Latest commit: 3eed3b5

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

This PR includes changesets to release 1 package

Name	Type
viem	Patch

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