Expose plugin ownership in MCP server status (#37850)

## What changed

- Add `pluginId` to each `mcpServerStatus/list` result.
- Populate it for MCP servers contributed by installed or selected plugins, and
  return `null` for servers from other sources.
- Update the generated protocol schemas, TypeScript bindings, and app-server
  documentation.

## Testing

- Cover plugin-owned servers in plugin installation and executor flows.
- Verify non-plugin servers and protocol serialization return a null
  `pluginId`.

GitOrigin-RevId: 0e4b912252cf51be56dcb63e0c1c7365a5e870ee

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

@@ -61,6 +61,7 @@ pub enum McpServerStatusDetail {
 #[ts(export_to = "v2/")]
 pub struct McpServerStatus {
     pub name: String,
+    pub plugin_id: Option<String>,
     pub server_info: Option<McpServerInfo>,
     pub tools: std::collections::HashMap<String, McpTool>,
     pub resources: Vec<McpResource>,

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

@@ -2422,6 +2422,7 @@ fn mcp_server_status_serializes_absent_server_info_as_null() {
     let response = ListMcpServerStatusResponse {
         data: vec![McpServerStatus {
             name: "not-ready".to_string(),
+            plugin_id: None,
             server_info: None,
             tools: HashMap::new(),
             resources: Vec::new(),
@@ -2436,6 +2437,7 @@ fn mcp_server_status_serializes_absent_server_info_as_null() {
         json!({
             "data": [{
                 "name": "not-ready",
+                "pluginId": null,
                 "serverInfo": null,
                 "tools": {},
                 "resources": [],
@@ -2507,6 +2509,7 @@ fn mcp_server_status_serializes_absent_server_info_metadata_as_null() {
     let response = ListMcpServerStatusResponse {
         data: vec![McpServerStatus {
             name: "initialized".to_string(),
+            plugin_id: Some("lookup@test".to_string()),
             server_info: Some(McpServerInfo {
                 name: "lookup-server".to_string(),
                 title: None,
@@ -2528,6 +2531,7 @@ fn mcp_server_status_serializes_absent_server_info_metadata_as_null() {
         json!({
             "data": [{
                 "name": "initialized",
+                "pluginId": "lookup@test",
                 "serverInfo": {
                     "name": "lookup-server",
                     "title": null,