New examples

[canack]

Add System Monitor and News Reader Examples

This PR adds two new examples that demonstrate different use cases of the Skeleton TUI library.

System Monitor Example

Features

• Three tabs showing different system metrics:
  • CPU usage with real-time updates
  • Memory usage with GB and percentage display
  • Disk usage showing used and free space
• Dynamic progress bars that change colors based on usage thresholds
• Tab-specific colors that change when switching between tabs
• Real-time updates every second
• Time widget showing current system time

Technical Details

• Uses gopsutil library for system metrics
• Demonstrates how to handle IAMActivePage messages for tab-specific styling
• Shows proper usage of UpdateMsg for periodic updates
• Implements progress bars with warning/critical thresholds

News Reader Example

Features

• Main news list tab showing:
  • Article titles with read/unread status
  • Interactive selection with keyboard navigation
  • Loading and error states
• Dynamic detail tabs for each article showing:
  • Article title and publication date
  • Full article content
  • Original article link
• Status widgets showing:
  • Total and unread article counts
  • Current system time
• Gruvbox-inspired color theme

Technical Details

• Uses gofeed library for RSS feed parsing
• Demonstrates dynamic tab creation and deletion
• Shows proper handling of async operations (RSS feed fetching)
• Implements keyboard navigation (j/k, arrows, enter, ctrl+w)
• Uses IAMActivePage messages for tab-specific styling

Screenshots

[Screenshots can be added here]

Usage

System Monitor:

cd examples/system-monitor
go mod tidy
go run main.go

News Reader:

cd examples/news-reader
go mod tidy
go run main.go

These examples serve as practical demonstrations of:

• Tab management (static and dynamic)
• Widget updates and real-time data
• Async operations and error handling
• Keyboard navigation
• Custom styling and theming
• Message handling