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/core/tests/suite/code_mode.rs

@@ -2280,7 +2280,14 @@ text(JSON.stringify(tool));
         parsed,
         serde_json::json!({
             "name": "mcp__rmcp__echo",
-            "description": "Echo back the provided message and include environment data.\n\nexec tool declaration:\n```ts\ndeclare const tools: { mcp__rmcp__echo(args: { env_var?: string; message: string; }): Promise<{ _meta?: unknown; content: Array<unknown>; isError?: boolean; structuredContent?: unknown; }>; };\n```",
+            "description": concat!(
+                "Echo back the provided message and include environment data.\n\n",
+                "exec tool declaration:\n",
+                "```ts\n",
+                "declare const tools: { mcp__rmcp__echo(args: { env_var?: string; message: string; }): ",
+                "Promise<CallToolResult<{ echo: string; env: string | null; }>>; };\n",
+                "```",
+            ),
         })
     );