Summary

Add PEP 723 inline script metadata to examples/echo_agent.py so the example can be launched directly with uv run.

This makes Quickstart easier (especially Step 2 and Step 3):

uv run examples/echo_agent.py

{
  "agent_servers": {
    "Echo Agent (Python)": {
      "type": "custom",
      "command": "uv",
      "args": [
        "run",
        "/abs/path/to/agentclientprotocol/python-sdk/examples/echo_agent.py"
      ]
    }
  }
}

Related issues

N/A

Testing

• uv run examples/echo_agent.py
  • Confirmed the script starts under uv run and waits for stdio-based ACP communication.

Docs & screenshots

No docs updated in this PR.

Checklist

• Conventional Commit title (e.g. feat:, fix:).
• Tests cover the change or are not required (explain above).
• Docs/examples updated when behaviour is user-facing.
• Schema regenerations (make gen-all) are called out if applicable.