fix: get account with base64+zstd

[Arrowana]

This should work out of the box, that's also the rust solana-rpc-client default

[greptile-apps]

Greptile Summary

Enables zstd support for Solana account decoder client types and adds coverage for Base64Zstd account responses.

• Activates the zstd feature on the shared solana-account-decoder-client-types dependency.
• Verifies that getAccountInfo returns Base64Zstd data that decodes to the original account.

Confidence Score: 5/5

The PR appears safe to merge, with no concrete changed-code failure identified.

The dependency feature is paired with a test that exercises the production getAccountInfo encoding path and validates a complete Base64Zstd round trip.

Important Files Changed

Filename	Overview
Cargo.toml	Enables the decoder client-types zstd feature used for Base64Zstd account serialization and deserialization.
crates/core/src/rpc/accounts_data.rs	Adds an end-to-end RPC unit test covering Base64Zstd encoding and round-trip account decoding.

_{Reviews (1): Last reviewed commit: "fix: get account with base64+zstd" | Re-trigger Greptile}

[MicaiahReid]

Thanks for the PR, @Arrowana! Was this an issue you had? It's great to have the test, but it passes without the associated dep change, so I want to be sure we're fixing any underlying issue you had

[MicaiahReid]

I removed this feature and the test above still passed. Are we sure it's needed?

[Arrowana]

Both solana-account-decoder and solana-rpc-client already enable solana-account-decoder-client-types/zstd

https://github.com/anza-xyz/agave/blob/d32fc31eb1717f534466fca42eea7848e335ef4d/account-decoder/Cargo.toml#L30

so yes that's indeed incorrect, i think the symptoms are similar to #738 but the root cause was misdiagnosed wildly