Fix workspace configuration error with structured_output_lowlevel.py

[lorenss-m]

Motivation and Context

The workspace configuration in pyproject.toml uses glob pattern examples/servers/* expecting all items to be packages with their own pyproject.toml. However, structured_output_lowlevel.py is a standalone file, causing uv sync to fail when installing the SDK as a git dependency.

How Has This Been Tested?

• Created proper package structure for the example
• Verified uv sync works correctly

Breaking Changes

None. The example functionality remains identical.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

Moved examples/servers/structured_output_lowlevel.py to examples/servers/structured-output-lowlevel/mcp_structured_output_lowlevel/__main__.py with proper package structure.