Add app-server marketplace upgrade RPC (#19074)

## Summary
- add a v2 `marketplace/upgrade` app-server RPC that mirrors the
existing configured Git marketplace upgrade path
- expose typed request/response/error payloads and regenerate
JSON/TypeScript schema fixtures
- add app-server integration coverage for all, named, already
up-to-date, and invalid marketplace upgrade requests

## Tests
- `just write-app-server-schema`
- `cargo test -p codex-app-server-protocol`
- `cargo test -p codex-app-server marketplace_upgrade`
- `just fix -p codex-app-server-protocol`
- `just fix -p codex-app-server`
- `just fmt`

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

@@ -88,6 +88,9 @@ use codex_app_server_protocol::MarketplaceAddResponse;
 use codex_app_server_protocol::MarketplaceInterface;
 use codex_app_server_protocol::MarketplaceRemoveParams;
 use codex_app_server_protocol::MarketplaceRemoveResponse;
+use codex_app_server_protocol::MarketplaceUpgradeErrorInfo;
+use codex_app_server_protocol::MarketplaceUpgradeParams;
+use codex_app_server_protocol::MarketplaceUpgradeResponse;
 use codex_app_server_protocol::McpResourceReadParams;
 use codex_app_server_protocol::McpResourceReadResponse;
 use codex_app_server_protocol::McpServerOauthLoginCompletedNotification;
@@ -980,6 +983,10 @@ impl CodexMessageProcessor {
                 self.marketplace_remove(to_connection_request_id(request_id), params)
                     .await;
             }
+            ClientRequest::MarketplaceUpgrade { request_id, params } => {
+                self.marketplace_upgrade(to_connection_request_id(request_id), params)
+                    .await;
+            }
             ClientRequest::PluginList { request_id, params } => {
                 self.plugin_list(to_connection_request_id(request_id), params)
                     .await;
@@ -6776,6 +6783,61 @@ impl CodexMessageProcessor {
             }
         }
     }
+
+    async fn marketplace_upgrade(
+        &self,
+        request_id: ConnectionRequestId,
+        params: MarketplaceUpgradeParams,
+    ) {
+        let config = match self.load_latest_config(/*fallback_cwd*/ None).await {
+            Ok(config) => config,
+            Err(err) => {
+                self.outgoing.send_error(request_id, err).await;
+                return;
+            }
+        };
+        let plugins_manager = self.thread_manager.plugins_manager();
+        let MarketplaceUpgradeParams { marketplace_name } = params;
+
+        let result = tokio::task::spawn_blocking(move || {
+            plugins_manager
+                .upgrade_configured_marketplaces_for_config(&config, marketplace_name.as_deref())
+        })
+        .await;
+
+        match result {
+            Ok(Ok(outcome)) => {
+                self.outgoing
+                    .send_response(
+                        request_id,
+                        MarketplaceUpgradeResponse {
+                            selected_marketplaces: outcome.selected_marketplaces,
+                            upgraded_roots: outcome.upgraded_roots,
+                            errors: outcome
+                                .errors
+                                .into_iter()
+                                .map(|err| MarketplaceUpgradeErrorInfo {
+                                    marketplace_name: err.marketplace_name,
+                                    message: err.message,
+                                })
+                                .collect(),
+                        },
+                    )
+                    .await;
+            }
+            Ok(Err(message)) => {
+                self.send_invalid_request_error(request_id, message).await;
+            }
+            Err(err) => {
+                self.send_internal_error(
+                    request_id,
+                    format!("failed to upgrade marketplaces: {err}"),
+                )
+                .await;
+            }
+        }
+    }
+
     async fn marketplace_add(&self, request_id: ConnectionRequestId, params: MarketplaceAddParams) {
         let result = add_marketplace_to_codex_home(
             self.config.codex_home.to_path_buf(),