Create Example Usage Code

[Technical-1]

Priority: Low
Labels: documentation, enhancement

Description:
Create examples/ directory with example usage code. Add example showing how to use SystemMonitor as library and example for custom dashboard extensions.

Files to create:

• examples/basic_usage.rs
• examples/custom_dashboard.rs

Acceptance criteria:

• examples/ directory created
• Basic usage example showing SystemMonitor usage
• Custom dashboard example showing extension patterns
• Examples compile and run successfully
• Examples documented in README

Implementation notes:

• Create examples/ directory
• Add [[example]] sections to Cargo.toml
• Create basic example showing how to use SystemMonitor
• Create advanced example showing custom dashboard
• Update README with examples section