fix(rpc-json): disable key-wallet default features

rpc-json only needs key-wallet for type definitions and serde.
Without default-features = false, it pulls in the manager module
(tokio, rayon) which inflates WASM builds that depend on
dashcore-rpc transitively.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: shumkov

rpc-json/Cargo.toml

@@ -25,7 +25,7 @@ serde_with = "2.1.0"
 serde_repr = "0.1"
 hex = { version="0.4", features=["serde"]}
 
-key-wallet = { path = "../key-wallet", features=["serde"] }
+key-wallet = { path = "../key-wallet", default-features = false, features=["std", "serde"] }
 dashcore = { path = "../dash", features=["secp-recovery", "rand-std", "signer", "serde"] }
 
 bincode = { version = "2.0.1", features = ["serde"] }