Describe the bug

Per this section of the MCP Apps spec, the host is supposed to forward the entire tool execution result to the MCP App view, including the _meta property.

Goose 1.24.0 did this correctly, but Goose 1.25.0 no longer includes _meta. The regression was introduced in #7013, specifically here:

To Reproduce
Steps to reproduce the behavior:

// server
registerAppTool(
  server,
  "show-mcp-app",
  {
    title: "Show MCP App",
    description: "Show MCP App",
    _meta: { ui: { resourceUri: MCP_APP_URI } },
  },
  async () => {
    return {
      content: [{ type: "text", text: "App" }],
      _meta: { message: "hello world" },
    };
  },
);

// client
app.ontoolresult = (result) => {
  console.log(result);
}

Expected behavior
When the MCP App renders in the host, it should print an object containing "hello world" to the console.

Screenshots
n/a

Please provide the following information

• OS & Arch: macOS 15.7.4. arm64
• Interface: UI
• Version: 1.25.0
• Extensions enabled: MCP Apps
• Provider & Model: n/a

Additional context
Add any other context about the problem here.