cargo: Mark some deps as optional for rpc_server feature.

Cargo.toml

@@ -13,13 +13,16 @@ thiserror = "1.0.63"
 bitcoin-scriptexec = { git = "https://github.com/Bitcoin-Wildlife-Sanctuary/rust-bitcoin-scriptexec" }
 rusqlite = { version = "0.32.1", features = ["bundled"] }
 rs_merkle = "1.4"
-jsonrpsee = { version = "0.24.3", features = ["server", "client", "macros"], default-features = false }
-tokio = { version = "1.39.3", features = ["full"]}
 tracing = "0.1.40"
 tracing-subscriber = { version = "0.3.18", features = ["env-filter"] }
-tower = "0.4.13"
 clap = { version = "4.5.16", features = ["derive"] }
+jsonrpsee = { version = "0.24.3", features = ["server", "client", "macros"], default-features = false, optional = true }
+tokio = { version = "1.39.3", features = ["full"], optional = true }
+tower = { version = "0.4.13", optional = true }
+
+[dev-dependencies]
+tokio = { version = "1.39.3", features = ["full"] }
 
 [features]
 # Enables RPC server interface. Note: Not stable nor complete. Use it in your own caution.
-rpc_server = []
+rpc_server = ["dep:jsonrpsee", "dep:tokio", "dep:tower"]