Finish moving codex exec to app-server (#15424)

This PR completes the conversion of non-interactive `codex exec` to use
app server rather than directly using core events and methods.

### Summary
- move `codex-exec` off exec-owned `AuthManager` and `ThreadManager`
state
- route exec bootstrap, resume, and auth refresh through existing
app-server paths
- replace legacy `codex/event/*` decoding in exec with typed app-server
notification handling
- update human and JSONL exec output adapters to translate existing
app-server notifications only
- clean up "app server client" layer by eliminating support for legacy
notifications; this is no longer needed
- remove exposure of `authManager` and `threadManager` from "app server
client" layer

### Testing
- `exec` has pretty extensive unit and integration tests already, and
these all pass
- In addition, I asked Codex to put together a comprehensive manual set
of tests to cover all of the `codex exec` functionality (including
command-line options), and it successfully generated and ran these tests

codex-rs/app-server/src/in_process.rs

@@ -68,14 +68,11 @@ use codex_app_server_protocol::ClientRequest;
 use codex_app_server_protocol::ConfigWarningNotification;
 use codex_app_server_protocol::InitializeParams;
 use codex_app_server_protocol::JSONRPCErrorError;
-use codex_app_server_protocol::JSONRPCNotification;
 use codex_app_server_protocol::RequestId;
 use codex_app_server_protocol::Result;
 use codex_app_server_protocol::ServerNotification;
 use codex_app_server_protocol::ServerRequest;
 use codex_arg0::Arg0DispatchPaths;
-use codex_core::AuthManager;
-use codex_core::ThreadManager;
 use codex_core::config::Config;
 use codex_core::config_loader::CloudRequirementsLoader;
 use codex_core::config_loader::LoaderOverrides;
@@ -98,16 +95,6 @@ fn server_notification_requires_delivery(notification: &ServerNotification) -> b
     matches!(notification, ServerNotification::TurnCompleted(_))
 }
 
-fn legacy_notification_requires_delivery(notification: &JSONRPCNotification) -> bool {
-    matches!(
-        notification
-            .method
-            .strip_prefix("codex/event/")
-            .unwrap_or(&notification.method),
-        "task_complete" | "turn_aborted" | "shutdown_complete"
-    )
-}
-
 /// Input needed to start an in-process app-server runtime.
 ///
 /// These fields mirror the pieces of ambient process state that stdio and
@@ -124,10 +111,6 @@ pub struct InProcessStartArgs {
     pub loader_overrides: LoaderOverrides,
     /// Preloaded cloud requirements provider.
     pub cloud_requirements: CloudRequirementsLoader,
-    /// Optional prebuilt auth manager reused by an embedding caller.
-    pub auth_manager: Option<Arc<AuthManager>>,
-    /// Optional prebuilt thread manager reused by an embedding caller.
-    pub thread_manager: Option<Arc<ThreadManager>>,
     /// Feedback sink used by app-server/core telemetry and logs.
     pub feedback: CodexFeedback,
     /// Startup warnings emitted after initialize succeeds.
@@ -144,11 +127,6 @@ pub struct InProcessStartArgs {
 
 /// Event emitted from the app-server to the in-process client.
 ///
-/// The stream carries three event families because CLI surfaces are mid-migration
-/// from the legacy `codex_protocol::Event` model to the typed app-server
-/// notification model. Once all surfaces consume only [`ServerNotification`],
-/// [`LegacyNotification`](Self::LegacyNotification) can be removed.
-///
 /// [`Lagged`](Self::Lagged) is a transport health marker, not an application
 /// event — it signals that the consumer fell behind and some events were dropped.
 #[derive(Debug, Clone)]
@@ -157,8 +135,6 @@ pub enum InProcessServerEvent {
     ServerRequest(ServerRequest),
     /// App-server notification directed to the embedded client.
     ServerNotification(ServerNotification),
-    /// Legacy JSON-RPC notification from core event bridge.
-    LegacyNotification(JSONRPCNotification),
     /// Indicates one or more events were dropped due to backpressure.
     Lagged { skipped: usize },
 }
@@ -390,7 +366,6 @@ fn start_uninitialized(args: InProcessStartArgs) -> InProcessClientHandle {
                 Arc::clone(&outbound_initialized),
                 Arc::clone(&outbound_experimental_api_enabled),
                 Arc::clone(&outbound_opted_out_notification_methods),
-                /*allow_legacy_notifications*/ true,
                 /*disconnect_sender*/ None,
             ),
         );
@@ -410,8 +385,6 @@ fn start_uninitialized(args: InProcessStartArgs) -> InProcessClientHandle {
                 cli_overrides: args.cli_overrides,
                 loader_overrides: args.loader_overrides,
                 cloud_requirements: args.cloud_requirements,
-                auth_manager: args.auth_manager,
-                thread_manager: args.thread_manager,
                 feedback: args.feedback,
                 log_db: None,
                 config_warnings: args.config_warnings,
@@ -655,32 +628,6 @@ fn start_uninitialized(args: InProcessStartArgs) -> InProcessClientHandle {
                                 }
                             }
                         }
-                        OutgoingMessage::Notification(notification) => {
-                            let notification = JSONRPCNotification {
-                                method: notification.method,
-                                params: notification.params,
-                            };
-                            if legacy_notification_requires_delivery(&notification) {
-                                if event_tx
-                                    .send(InProcessServerEvent::LegacyNotification(notification))
-                                    .await
-                                    .is_err()
-                                {
-                                    break;
-                                }
-                            } else if let Err(send_error) =
-                                event_tx.try_send(InProcessServerEvent::LegacyNotification(notification))
-                            {
-                                match send_error {
-                                    mpsc::error::TrySendError::Full(_) => {
-                                        warn!("dropping in-process legacy notification (queue full)");
-                                    }
-                                    mpsc::error::TrySendError::Closed(_) => {
-                                        break;
-                                    }
-                                }
-                            }
-                        }
                     }
                 }
             }
@@ -759,8 +706,6 @@ mod tests {
             cli_overrides: Vec::new(),
             loader_overrides: LoaderOverrides::default(),
             cloud_requirements: CloudRequirementsLoader::default(),
-            auth_manager: None,
-            thread_manager: None,
             feedback: CodexFeedback::new(),
             config_warnings: Vec::new(),
             session_source,
@@ -858,7 +803,7 @@ mod tests {
     }
 
     #[test]
-    fn guaranteed_delivery_helpers_cover_terminal_notifications() {
+    fn guaranteed_delivery_helpers_cover_terminal_server_notifications() {
         assert!(server_notification_requires_delivery(
             &ServerNotification::TurnCompleted(TurnCompletedNotification {
                 thread_id: "thread-1".to_string(),
@@ -870,30 +815,5 @@ mod tests {
                 },
             })
         ));
-
-        assert!(legacy_notification_requires_delivery(
-            &JSONRPCNotification {
-                method: "codex/event/task_complete".to_string(),
-                params: None,
-            }
-        ));
-        assert!(legacy_notification_requires_delivery(
-            &JSONRPCNotification {
-                method: "codex/event/turn_aborted".to_string(),
-                params: None,
-            }
-        ));
-        assert!(legacy_notification_requires_delivery(
-            &JSONRPCNotification {
-                method: "codex/event/shutdown_complete".to_string(),
-                params: None,
-            }
-        ));
-        assert!(!legacy_notification_requires_delivery(
-            &JSONRPCNotification {
-                method: "codex/event/item_started".to_string(),
-                params: None,
-            }
-        ));
     }
 }