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/lib.rs

@@ -44,6 +44,7 @@ pub use apply_patch_tool::ApplyPatchToolArgs;
 pub use apply_patch_tool::create_apply_patch_freeform_tool;
 pub use apply_patch_tool::create_apply_patch_json_tool;
 pub use code_mode::augment_tool_spec_for_code_mode;
+pub use code_mode::collect_code_mode_exec_prompt_tool_definitions;
 pub use code_mode::collect_code_mode_tool_definitions;
 pub use code_mode::create_code_mode_tool;
 pub use code_mode::create_wait_tool;