RUSTSEC-2026-0014 `rpc-check` was removed from crates.io for malicious code

It was attempting to steal credentials from the POLYMARKETPRIVATEKEY environment variable. The malicious crate had 3 versions published on 2026-02-15 and had been downloaded only 155 times. There were no crates depending on this crate on crates.io. Thanks to Sisong Li for finding and reporting th...