Make Aquila gRPC channel timeouts configurable

[raphael-goetz]

Draco hardcoded Aquila gRPC channel timeouts in crates/base/src/client/mod.rs with a 2s connect timeout and a 10s request timeout. These should be configurable for deployments where Aquila responses or connections can legitimately take longer.\n\nProposed fix: add env-backed timeout settings to AdapterConfig and pass them into the runtime status client channel setup.\n\nEnv vars:\n- AQUILA_GRPC_CONNECT_TIMEOUT_SECS, default 2\n- AQUILA_GRPC_REQUEST_TIMEOUT_SECS, default 10