Add output_schema to code mode render (#17210)

This updates code-mode tool rendering so MCP tools can surface
structured output types from their `outputSchema`.

What changed:
- Detect MCP tool-call result wrappers from the output schema shape
instead of relying on tool-name parsing or provenance flags.
- Render shared TypeScript aliases once for MCP tool results
(`CallToolResult`, `ContentBlock`, etc.) so multiple MCP tool
declarations stay compact.
- Type `structuredContent` from the tool definition's `outputSchema`
instead of rendering it as `unknown`.
- Update the shared MCP aliases to match the MCP draft `CallToolResult`
schema more closely.

Example:
- Before: `declare const tools: { mcp__rmcp__echo(args: { env_var?:
string; message: string; }): Promise<{ _meta?: unknown; content:
Array<unknown>; isError?: boolean; structuredContent?: unknown; }>; };`
- After: `declare const tools: { mcp__rmcp__echo(args: { env_var?:
string; message: string; }): Promise<CallToolResult<{ echo: string; env:
string | null; }>>; };`

codex-rs/tools/src/code_mode_tests.rs

@@ -182,7 +182,13 @@ fn create_wait_tool_matches_expected_spec() {
 
 #[test]
 fn create_code_mode_tool_matches_expected_spec() {
-    let enabled_tools = vec![("update_plan".to_string(), "Update the plan".to_string())];
+    let enabled_tools = vec![codex_code_mode::ToolDefinition {
+        name: "update_plan".to_string(),
+        description: "Update the plan".to_string(),
+        kind: codex_code_mode::CodeModeToolKind::Function,
+        input_schema: None,
+        output_schema: None,
+    }];
 
     assert_eq!(
         create_code_mode_tool(