Implement comprehensive history visualization with floating timeline controls

[mentatbot]

This PR adds a complete history visualization system that allows users to explore repository evolution over time through an interactive timeline interface.

Key Features

Timeline Visualization

• Displays repository evolution across commit history with configurable sampling
• Shows file lifecycle indicators (added/removed/renamed files)
• Maintains node position continuity between timeline points for smooth transitions
• Supports chronological playback from oldest to newest commits

Floating Timeline Controls

• Fully draggable floating panel positioned independently of page layout
• Play/pause animation with adjustable speed controls
• Timeline scrubber for instant navigation to any commit
• Branch selection dropdown (shows current analyzed branch)
• Current commit information display with change statistics

Enhanced User Experience

• Keyboard shortcuts (Space for play/pause, arrows for navigation, Home/End for jumping)
• Visual timeline indicator overlay showing current commit SHA
• Toggle button to show/hide history controls
• Smooth transitions with loading overlays during timeline changes

Technical Improvements

• Repository analyzer generates comprehensive timeline data with commit snapshots
• Support for branch-specific analysis with --branch parameter
• Enhanced CLI with history sampling options (--history-sample, --max-commits)
• Fixed icon rendering issues by replacing problematic SVGs with text symbols
• Proper z-index management for floating UI components

Merged Updates

• Integrates latest legend improvements and visualization enhancements from main branch
• Updated dependencies and resolved merge conflicts
• Maintains compatibility with existing visualization controls

The history feature automatically activates when repository data contains timeline points, providing users with a powerful way to understand how their codebase has evolved over time.

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