feat: Add real-time system status dashboard (fub status)

[therealtinhtute]

Implemented a comprehensive system health monitoring dashboard inspired by Mole's mo status feature, adapted for Ubuntu/Linux systems.

Features:

• Real-time system metrics collection:
  • CPU: Usage %, load averages, per-core stats, temperature
  • Memory: RAM usage, swap usage, available memory
  • Disk: Space usage with color-coded alerts, I/O read/write speeds
  • Network: Active interface, download/upload speeds
  • System: OS info, kernel, uptime, process count

• Health Score System:
  • Calculates overall system health (0-100)
  • Weighted scoring based on CPU (30%), Memory (30%), Disk (20%), Load (20%)
  • Color-coded display: Green (80+), Yellow (60-79), Red (<60)
  • Health status: Excellent, Good, Fair, Poor

• Interactive Dashboard:
  • Auto-refresh every 5 seconds
  • Manual refresh with 'R' key
  • Clean, organized terminal UI with sections
  • Shows top 5 processes by CPU and memory
  • Color-coded metrics based on thresholds

• Integration:
  • Added to main fub menu as option 1
  • Accessible via "fub status" command
  • Auto-installs dependencies (bc, sysstat) if missing

Technical Implementation:

• Uses /proc filesystem for metrics
• Linux-specific commands (mpstat, df, ps, top)
• Bash arithmetic and awk for calculations
• Consistent with fub's color scheme and UX

Addresses Mole update analysis for Ubuntu/Linux compatibility.