test(acp): expect typed missing-session errors

Author: NathanFlurry

crates/agentos-sidecar/tests/acp_adapter_restart.rs

@@ -186,7 +186,7 @@ fn adapter_crash_restarts_or_evicts_and_emits_exit_event() {
     let AcpResponse::AcpErrorResponse(AcpErrorResponse { code, message }) = response else {
         panic!("expected the post-eviction prompt to fail, got: {response:?}");
     };
-    assert_eq!(code, "invalid_state");
+    assert_eq!(code, "session_not_found");
     assert!(
         message.contains("unknown ACP session"),
         "expected unknown-session error after eviction, got: {message}"

crates/agentos-sidecar/tests/acp_extension.rs

@@ -1061,7 +1061,7 @@ fn acp_session_request_denies_cross_connection_prompt_and_cancel() {
 }
 
 /// Assert an ACP response is a deny that is INDISTINGUISHABLE from a missing
-/// session: the shared ACP core's `invalid_state` code and unknown-session
+/// session: the shared ACP core's `session_not_found` code and unknown-session
 /// message. This locks in the no-existence-leak property
 /// — a non-owner must learn nothing (not even that the session exists), so a
 /// regression to a distinguishable error (e.g. an `unauthorized` code) fails here.
@@ -1071,7 +1071,7 @@ fn assert_indistinguishable_deny(response: AcpResponse, what: &str) {
         panic!("{what} must be DENIED with an error response, but it returned: {response:?}");
     };
     assert_eq!(
-        error.code, "invalid_state",
+        error.code, "session_not_found",
         "{what} must fail closed with the same code as a missing session (no \
          'unauthorized' existence oracle); got code {:?} / message {:?}",
         error.code, error.message

crates/agentos-sidecar/tests/acp_wrapper_conformance.rs

@@ -437,7 +437,7 @@ fn native_and_browser_wrappers_match_full_session_lifecycle() {
         );
         assert_eq!(
             native_step.response["code"],
-            json!("invalid_state"),
+            json!("session_not_found"),
             "cross-owner {label} must fail closed without revealing the session",
         );
         assert!(native_step.events.is_empty());