test: add integration tests for ETH RPC endpoints

Add 23 integration tests covering all endpoint categories: simple
queries, block/transaction lookups, account state, logs, and error
cases. Tests exercise the router through the axum service layer using
tower's oneshot().

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: prestwich

crates/rpc-storage/Cargo.toml

@@ -27,3 +27,15 @@ serde.workspace = true
 
 [dev-dependencies]
 tokio = { workspace = true, features = ["macros", "rt-multi-thread"] }
+tokio-util = "0.7"
+signet-cold = { workspace = true, features = ["test-utils"] }
+signet-hot = { workspace = true, features = ["test-utils"] }
+signet-storage.workspace = true
+signet-storage-types.workspace = true
+signet-constants.workspace = true
+alloy.workspace = true
+serde_json.workspace = true
+axum = "0.8"
+tower = { version = "0.5", features = ["util"] }
+http = "1"
+trevm.workspace = true