Refactor Rust A2A service into gateway_rs crate

Reorganize and modernize the Rust A2A service: move mcpgateway_rust into crates/gateway_rs/services/a2a_service, add a new lib.rs PyO3 extension and queue.rs, and update Cargo.toml workspace membership and dependencies. Refactor invoker to accept indexed batch requests and return indexed results (preserving ordering), add A2AInvokeRequest/A2AInvokeResult types, and update unit tests to the new API. Update packaging metadata (pyproject) to expose gateway_rs.a2a_service, add Makefile targets for building/installing/testing gateway Rust crates, and remove legacy mcpgateway_rust artifacts and differential benchmark files.

Signed-off-by: Luca <lucarlig@protonmail.com>

Author: lucarlig

Cargo.lock

@@ -1,7 +1,7 @@
 [workspace]
 resolver = "3"
 members = [
-    "crates/mcpgateway/*",
+    "crates/gateway_rs/services/*",
     "crates/tools/*",
     "crates/mcp-servers/*",
     "crates/plugins/*",
@@ -33,6 +33,15 @@ tokio = { version = "1.49", features = ["full"] }
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 
+# Error handling
+thiserror = "2.0"
+
+# Concurrent collections
+dashmap = "6.1"
+
+# URL parsing (for A2A auth query params)
+url = "2.5"
+
 [profile.release]
 opt-level = 3
 lto = "fat"