install serena-agent on VS Code

Requires Python 3.10+ and uvx (install with `pipx install uv`) so the package can be resolved on first run. VS Code (Copilot) uses a `servers` root key with an explicit `type` field — different from the `mcpServers` shape used by Claude Desktop and Cursor. Paste the config below, then follow the reload step to register serena-agent.

{
  "servers": {
    "serena-agent": {
      "type": "stdio",
      "command": "uvx",
      "args": [
        "serena-agent"
      ]
    }
  }
}