Add ERA chain and ETKN native asset

[erablockchains]

This PR adds ERA as a standalone Substrate chain and ETKN as its native asset.

Network details:

• Name: ERA
• Chain type: Standalone Substrate / solo chain
• Genesis hash: ba96ed0fe6c37790ee7da7ed9e83e9630b29fc8ba66e6753dc2e5c5704aa94e7
• RPC: wss://eraprojects.org/
• Native token: ETKN
• Decimals: 18
• SS58/address prefix: 42
• Website: https://eraprojects.io/
• Network page: https://eraprojects.io/network.html
• Support: support@eraprojects.io

Validation:

• Manual custom-network add in SubWallet tested successfully
• Send/receive works
• Public RPC is live and stable
• ERA-specific invariant check passed

Note:
Full repository validation commands were attempted, but they were blocked in the Codespace by Corepack cache / missing node_modules and Node JSON import assertion syntax issues. No unrelated generated files were changed.

[erablockchains]

Hello SubWallet team,

We opened a PR to add ERA and ETKN to SubWallet-ChainList:

<PASTE_PR_LINK>

Network:

• Name: ERA
• Chain type: Standalone Substrate / solo chain
• Genesis hash: ba96ed0fe6c37790ee7da7ed9e83e9630b29fc8ba66e6753dc2e5c5704aa94e7
• RPC: wss://eraprojects.org/
• Native token: ETKN
• Decimals: 18
• SS58/address prefix: 42
• Website: https://eraprojects.io/
• Support: support@eraprojects.io

Manual custom-network add in SubWallet was tested successfully, and send/receive works.

Please let us know if any additional metadata, logo changes, validation steps, or indexing requirements are needed.