✨ Add --python option to xaibo init command

[MFA-X-AI]

Currently, initializing a new agent automatically pins the project to the lowest Python version supported by the framework. This PR introduces the --python flag, allowing users to override this default and explicitly specify their desired Python version.

Changes

• Added --python argument to the init subparser
• Modified uv init command construction to conditionally include --python flag

Usage

# Use uv's default (checks .python-version, then first Python on PATH)
uv xaibo init my_agent

# Explicitly specify Python version
uv xaibo init my_agent --python 3.12
uv xaibo init my_agent --python 3.13

Technical Details

• The --python flag is optional - when omitted, uv init uses its standard version resolution
• When provided, the value is passed directly to uv init --python <version>
• Supported values: 3.10, 3.11, 3.12, 3.13 (matching xaibo's supported versions)