feat: support basic doc generator for memov.

[IRONICBo]

Background

Adds AI-powered documentation generation with code analysis and visualization capabilities.

Features

• Multi-level documentation: Generate docs for commits, branches, or entire repositories
• Smart code analysis: AST-based parsing of Python modules, classes, and functions
• Mermaid diagrams: Auto-generate flowcharts, class diagrams, and sequence diagrams
• Git integration: Extract commit history and analyze changes
• Live preview: Web server for real-time doc preview
• LLM-powered: Uses LiteLLM for intelligent documentation generation