feat: wrap log configs in LogConfig, add log rotation

[MaojiaSheng]

• Create new LogConfig class to wrap all log-related configuration
• Update OpenVikingConfig to use nested log config instead of separate fields
• Add log rotation support with TimedRotatingFileHandler in logger.py
• Add configure_uvicorn_logging to make uvicorn use OpenViking's logging config
• Fix empty file being created in current directory by properly handling log.output=file in logging_init.py
• Update examples/ov.conf.example to use new nested log config structure
• Update init.py to export LogConfig and initialize_openviking_config

Description

Related Issue

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Refactoring (no functional changes)
• Performance improvement
• Test update

Changes Made

Testing

• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have tested this on the following platforms:
  • Linux
  • macOS
  • Windows

Checklist

• My code follows the project's coding style
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published

Screenshots (if applicable)

Additional Notes

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