Enhance Settings Window with Real-time Model Download Progress

[Copilot]

This PR implements comprehensive enhancements to the settings window download functionality, providing users with real-time download progress tracking, cancellation capability, and professional feedback similar to modern download managers.

🚀 Key Features Implemented

Real-time Download Progress

• Detailed Progress Display: Shows current/total file sizes (e.g., "127.3 MB / 169.8 MB (75.0%)")
• Download Speed: Real-time speed calculation and display (e.g., "2.3 MB/s")
• ETA Calculation: Estimated time remaining with smart formatting (e.g., "1m 42s")
• Progress Bar: Smooth updates every 0.5 seconds for responsive feedback

Enhanced User Control

• Download Cancellation: Cancel button appears during active downloads with immediate response
• Retry Functionality: One-click retry for failed downloads with proper cleanup
• Thread-safe Operations: Non-blocking downloads with proper UI state management

Improved Error Handling

• Specific Error Messages: Tailored messages for different failure types (404, timeout, connection)
• Better Recovery: Automatic cleanup of partial downloads on errors or cancellation
• User-friendly Feedback: Clear status messages throughout the download process

📊 Status Message Examples

Connecting: "Connecting to download server..."
Initial: "Downloading model... 0.0 MB / 169.8 MB (0.0%) - Initializing..."
Progress: "Downloading model... 127.3 MB / 169.8 MB (75.0%) - 2.3 MB/s - ETA: 18s"
Success: "Model 'vosk-model-small-en-us-0.15' installed successfully in 2m 15s"
Error: "Connection error - please check your internet connection"

🔧 Technical Implementation

Enhanced Download Worker

The _download_worker method now includes:

• Speed calculation based on download intervals: bytes_this_interval / elapsed_time
• ETA calculation using remaining bytes and current speed
• File size formatting in human-readable MB format
• Thread-safe cancellation mechanism with proper cleanup

UI Components

• Cancel Button: Appears during downloads with orange styling for visibility
• Retry Button: Shows after errors with blue styling for distinction
• Progress Bar: Enhanced layout with better positioning
• Status Label: Comprehensive information display with color-coded feedback

🎯 User Experience Improvements

Before: Basic progress bar with minimal information and no user control
After: Professional download experience with detailed metrics, user control, and comprehensive feedback

This enhancement transforms the model download process from a basic operation into a transparent, controllable experience that keeps users informed and provides them with the tools they need to manage downloads effectively.

🧪 Testing

• All syntax and compilation checks pass
• Enhanced functionality verified through comprehensive testing
• Error handling paths validated
• UI component integration confirmed
• Thread safety and cleanup mechanisms tested

The implementation provides immediate feedback when switching engines and downloading models, exactly as requested in the original issue requirements.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• esm.ubuntu.com
  • Triggering command: /usr/lib/apt/methods/https (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

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