[mcp] Support MCP Apps part 3 - Add mcp tool call support. (#17364)

- [x] Add a new app-server method so that MCP Apps can call their own
MCP server directly.

codex-rs/app-server-protocol/src/protocol/common.rs

@@ -470,6 +470,11 @@ client_request_definitions! {
         response: v2::McpResourceReadResponse,
     },
 
+    McpServerToolCall => "mcpServer/tool/call" {
+        params: v2::McpServerToolCallParams,
+        response: v2::McpServerToolCallResponse,
+    },
+
     WindowsSandboxSetupStart => "windowsSandbox/setupStart" {
         params: v2::WindowsSandboxSetupStartParams,
         response: v2::WindowsSandboxSetupStartResponse,