Fix: restore Rabbit Chain Testnet (9280)

[rabbitmainnet]

Summary

Restores Rabbit Chain Testnet (Chain ID 9280) to data/chains.json.

Rabbit Chain Testnet was previously reviewed and merged in #285 via merge commit 899f0405d812b7b32b895dd4a614641971f06406.

The entry was still present after that merge, but was unintentionally removed from data/chains.json by the later changes merged in #289 (7c2bd4c2a6).

This PR restores only the previously accepted Rabbit Chain Testnet entry.

Network

• Chain ID: 9280
• Name: Rabbit Chain Testnet
• Native currency: tRAB
• Layer: 1
• EVM compatible
• Testnet: yes
• Website: https://rabbitchain.org
• Explorer: https://explorer-testnet.rabbitchain.org/

Validation

• jq . data/chains.json > /dev/null ✅
• Official repository Docker build ✅
• git diff --check ✅
• Only data/chains.json is changed

Related:

• Original integration: Add Rabbit Chain Testnet (9280) #285
• Regression introduced after merge: Add DAC Interstellar Mainnet and Inception Testnet #289

[rabbitmainnet]

@NikitaSavik Hi — just flagging this because you merged the original Rabbit Chain Testnet integration in #285.

Rabbit Chain Testnet was successfully merged in #285 and was present on main afterward. It disappeared only after the later changes merged in #289, where the 9280 entry was removed from data/chains.json.

This PR does not introduce a new chain entry; it restores the exact Rabbit Chain Testnet configuration that had already been reviewed and merged.

We also re-ran the current repository checks locally: JSON validation passes, the Docker build succeeds, and only the 9280 block is restored.

Thanks for taking a look.