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-protocol/src/protocol/common.rs

@@ -649,6 +649,11 @@ client_request_definitions! {
         serialization: global("config"),
         response: v2::PluginShareListResponse,
     },
+    PluginShareCheckout => "plugin/share/checkout" {
+        params: v2::PluginShareCheckoutParams,
+        serialization: global("config"),
+        response: v2::PluginShareCheckoutResponse,
+    },
     PluginShareDelete => "plugin/share/delete" {
         params: v2::PluginShareDeleteParams,
         serialization: global("config"),

codex-rs/app-server-protocol/src/protocol/v2/plugin.rs

@@ -242,6 +242,26 @@ pub struct PluginShareListResponse {
     pub data: Vec<PluginShareListItem>,
 }
 
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct PluginShareCheckoutParams {
+    pub remote_plugin_id: String,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct PluginShareCheckoutResponse {
+    pub remote_plugin_id: String,
+    pub plugin_id: String,
+    pub plugin_name: String,
+    pub plugin_path: AbsolutePathBuf,
+    pub marketplace_name: String,
+    pub marketplace_path: AbsolutePathBuf,
+    pub remote_version: Option<String>,
+}
+
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
 #[serde(rename_all = "camelCase")]
 #[ts(export_to = "v2/")]

codex-rs/app-server-protocol/src/protocol/v2/tests.rs

@@ -2987,6 +2987,52 @@ fn plugin_share_params_and_response_serialization_use_camel_case_fields() {
         PluginShareListParams {},
     );
 
+    assert_eq!(
+        serde_json::to_value(PluginShareCheckoutParams {
+            remote_plugin_id: "plugins~Plugin_00000000000000000000000000000000".to_string(),
+        })
+        .unwrap(),
+        json!({
+            "remotePluginId": "plugins~Plugin_00000000000000000000000000000000",
+        }),
+    );
+
+    let plugin_path = if cfg!(windows) {
+        r"C:\Users\me\plugins\gmail"
+    } else {
+        "/Users/me/plugins/gmail"
+    };
+    let plugin_path = AbsolutePathBuf::try_from(PathBuf::from(plugin_path)).unwrap();
+    let plugin_path_json = plugin_path.as_path().display().to_string();
+    let marketplace_path = if cfg!(windows) {
+        r"C:\Users\me\.agents\plugins\marketplace.json"
+    } else {
+        "/Users/me/.agents/plugins/marketplace.json"
+    };
+    let marketplace_path = AbsolutePathBuf::try_from(PathBuf::from(marketplace_path)).unwrap();
+    let marketplace_path_json = marketplace_path.as_path().display().to_string();
+    assert_eq!(
+        serde_json::to_value(PluginShareCheckoutResponse {
+            remote_plugin_id: "plugins~Plugin_00000000000000000000000000000000".to_string(),
+            plugin_id: "gmail@codex-curated".to_string(),
+            plugin_name: "gmail".to_string(),
+            plugin_path,
+            marketplace_name: "codex-curated".to_string(),
+            marketplace_path,
+            remote_version: Some("1.2.3".to_string()),
+        })
+        .unwrap(),
+        json!({
+            "remotePluginId": "plugins~Plugin_00000000000000000000000000000000",
+            "pluginId": "gmail@codex-curated",
+            "pluginName": "gmail",
+            "pluginPath": plugin_path_json,
+            "marketplaceName": "codex-curated",
+            "marketplacePath": marketplace_path_json,
+            "remoteVersion": "1.2.3",
+        }),
+    );
+
     assert_eq!(
         serde_json::to_value(PluginShareDeleteParams {
             remote_plugin_id: "plugins~Plugin_00000000000000000000000000000000".to_string(),