v0.3.0 - Real-time selection previews

Added

• Two-phase processing architecture: Separate extraction/analysis from selection phase
• Interactive selection screen: Visual preview of frame selection with real-time feedback
• Sharpness visualization: Bar chart showing frame quality distribution (first 100 frames)
• Live selection preview: See frame count before applying selection
• Parameter adjustment: Fine-tune selection parameters with instant visual feedback

Changed

• TUI workflow: Now operates in distinct extraction and selection phases
• Selection process: Interactive with visual feedback instead of batch processing
• Resource efficiency: Analyze frames once, try multiple selection methods without reprocessing

Fixed

• Windows compatibility: FFmpeg process hanging on Windows with large videos
• Process termination: Proper subprocess cleanup with timeout handling
• Thread safety: Enhanced concurrent processing stability on Windows

Technical

• Two-phase TUIProcessor: New orchestrator for separated extraction and selection phases
• Selection preview API: Added preview_selection methods to processor and selector
• SharpnessChart widget: Custom Textual widget for frame quality visualization
• Windows FFmpeg fix: Proactive termination on frame count completion with stall detection