feat(acp-nats): add session_update client handler

- Add client proxy infrastructure (run loop, subject parsing)
- Add session_update handler for SessionNotification forwarding
- Add nats/parsing.rs with ClientMethod::SessionUpdate
- Add client subjects (session_update, wildcards)
- Add bytes, futures deps for subscriber stream
- Tests: session_update forwards, invalid payload, client error

Signed-off-by: Yordis Prieto <yordis.prieto@gmail.com>

Author: yordis

rsworkspace/Cargo.lock

@@ -8,9 +8,11 @@ workspace = true
 
 [dependencies]
 agent-client-protocol = "0.9.4"
-opentelemetry = "0.31.0"
 async-nats = "0.45.0"
 async-trait = "0.1.89"
+bytes = "1.9"
+futures = "0.3"
+opentelemetry = "0.31.0"
 serde = { version = "1.0.228", features = ["derive"] }
 serde_json = "1.0.149"
 tokio = { version = "1.49.0", features = ["rt", "macros", "sync", "time"] }