feat: Add plugin share checkout (#22435)

Adds plugin/share/checkout to turn a shared remote plugin into a local
working copy under ~/plugins/<name>.

Registers the copy in the managed personal marketplace and records the
remote-to-local mapping for later share/save flows.

---------

Co-authored-by: Codex <noreply@openai.com>

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

@@ -1099,6 +1099,9 @@ impl MessageProcessor {
             ClientRequest::PluginShareList { params, .. } => {
                 self.plugin_processor.plugin_share_list(params).await
             }
+            ClientRequest::PluginShareCheckout { params, .. } => {
+                self.plugin_processor.plugin_share_checkout(params).await
+            }
             ClientRequest::PluginShareDelete { params, .. } => {
                 self.plugin_processor.plugin_share_delete(params).await
             }

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

@@ -115,6 +115,8 @@ use codex_app_server_protocol::PluginListResponse;
 use codex_app_server_protocol::PluginMarketplaceEntry;
 use codex_app_server_protocol::PluginReadParams;
 use codex_app_server_protocol::PluginReadResponse;
+use codex_app_server_protocol::PluginShareCheckoutParams;
+use codex_app_server_protocol::PluginShareCheckoutResponse;
 use codex_app_server_protocol::PluginShareContext;
 use codex_app_server_protocol::PluginShareDeleteParams;
 use codex_app_server_protocol::PluginShareDeleteResponse;

codex-rs/app-server/src/request_processors/plugins.rs

@@ -313,6 +313,15 @@ impl PluginRequestProcessor {
             .map(|response| Some(response.into()))
     }
 
+    pub(crate) async fn plugin_share_checkout(
+        &self,
+        params: PluginShareCheckoutParams,
+    ) -> Result<Option<ClientResponsePayload>, JSONRPCErrorError> {
+        self.plugin_share_checkout_response(params)
+            .await
+            .map(|response| Some(response.into()))
+    }
+
     pub(crate) async fn plugin_share_delete(
         &self,
         params: PluginShareDeleteParams,
@@ -973,6 +982,42 @@ impl PluginRequestProcessor {
         Ok(PluginShareListResponse { data })
     }
 
+    async fn plugin_share_checkout_response(
+        &self,
+        params: PluginShareCheckoutParams,
+    ) -> Result<PluginShareCheckoutResponse, JSONRPCErrorError> {
+        let (config, auth) = self.load_plugin_share_config_and_auth().await?;
+        if !config.features.enabled(Feature::PluginSharing) {
+            return Err(invalid_request("plugin sharing is disabled"));
+        }
+        let PluginShareCheckoutParams { remote_plugin_id } = params;
+        if remote_plugin_id.is_empty() || !is_valid_remote_plugin_id(&remote_plugin_id) {
+            return Err(invalid_request("invalid remote plugin id"));
+        }
+
+        let remote_plugin_service_config = RemotePluginServiceConfig {
+            chatgpt_base_url: config.chatgpt_base_url.clone(),
+        };
+        let result = codex_core_plugins::remote::checkout_remote_plugin_share(
+            &remote_plugin_service_config,
+            auth.as_ref(),
+            config.codex_home.as_path(),
+            &remote_plugin_id,
+        )
+        .await
+        .map_err(|err| remote_plugin_catalog_error_to_jsonrpc(err, "checkout plugin share"))?;
+        self.clear_plugin_related_caches();
+        Ok(PluginShareCheckoutResponse {
+            remote_plugin_id: result.remote_plugin_id,
+            plugin_id: result.plugin_id,
+            plugin_name: result.plugin_name,
+            plugin_path: result.plugin_path,
+            marketplace_name: result.marketplace_name,
+            marketplace_path: result.marketplace_path,
+            remote_version: result.remote_version,
+        })
+    }
+
     async fn plugin_share_delete_response(
         &self,
         params: PluginShareDeleteParams,
@@ -1694,6 +1739,7 @@ fn remote_plugin_catalog_error_to_jsonrpc(
             invalid_request(message)
         }
         RemotePluginCatalogError::InvalidPluginPath { .. }
+        | RemotePluginCatalogError::PluginShareCheckoutNotAvailable { .. }
         | RemotePluginCatalogError::ArchiveTooLarge { .. }
         | RemotePluginCatalogError::UnknownMarketplace { .. } => invalid_request(message),
         RemotePluginCatalogError::AuthToken(_)