Function status_icon 

pub fn status_icon(status: &SpecStatus) -> ColoredString

Returns a colored status icon for the given spec status.

Icons:

• Pending: ○ (white)
• InProgress: ◐ (yellow)
• Completed: ● (green)
• Failed: ✗ (red)
• NeedsAttention: ⚠ (yellow)
• Ready: ◕ (cyan)
• Blocked: ⊗ (red)
• Cancelled: ✓ (dimmed)