feat(git): add date-based commit log retrieval functions

[Berg-it]

Description

Add git_log_date_range and git_log_by_date functions to retrieve commits within a date range or for a specific date. This enables users to filter commit history by date, which is useful for auditing and reporting purposes.

Motivation and Context

These changes align with the project's focus on providing granular Git history analysis tools while maintaining backward compatibility with existing integrations

How Has This Been Tested?

Tested with Trae IDE

Breaking Changes

Types of changes

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

Checklist

• [X] I have read the MCP Protocol Documentation
• [X] My changes follows MCP security best practices
• [X] I have updated the server's README accordingly
• [X] I have tested this with an LLM client
• [X] My code follows the repository's style guidelines
• [X] New and existing tests pass locally
• [ ] I have added appropriate error handling
• [ ] I have documented all environment variables and configuration options

Additional context