fix: bump etherscan api to v2

[imqdee]

The use of version 2 of the Etherscan API is now mandatory.
This update is required for the contract viewer page to function.

[vercel]

@imqdee is attempting to deploy a commit to the Duneanalytics Team on Vercel.

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[sanbir]

Follow-up implemented in my fork for issue #411:

• commit: 047ef6c (chore: improve etherscan v2 chainid and error handling)
• branch: sanbir/fix/bump-etherscan-api-v2

Could you please cherry-pick this commit into this PR branch so #398 also includes configurable chainid and clearer Etherscan error messages?

git cherry-pick 047ef6c

I can’t push directly to imqdee/evm.codes from my account (Permission denied).

[sanbir]

Opened helper PR with the follow-up commit here: imqdee#1

If that PR is merged, this PR (#398) will automatically include the changes.

[cursor]

PR Summary

Medium Risk
Changes how external Etherscan requests are formed (endpoint + required chainid), which can break contract-source fetching if env vars or query formatting are wrong; otherwise the change set is small.

Overview
Updates the Etherscan integration to call the mandatory v2 API endpoint (/v2/api) and includes a configurable chainid (via ETHERSCAN_CHAIN_ID, defaulting to 1) in all requests.

Refactors query construction to ensure all parameters are stringified and adds a safer default for missing APIKEY_ETHERSCAN. Improves etherscanParse failures by surfacing the underlying Etherscan error message/result in the thrown error string.

^{Written by Cursor Bugbot for commit 855cad5. Configure here.}

[imqdee]

thanks @sanbir , your changes has been included