Function format_coupling_project_text 

pub fn format_coupling_project_text(report: &CouplingReport) -> String

Format a project-wide coupling report as human-readable text.

Renders a ranked table of the highest-coupling module pairs with color coding:

• Tight (>= 0.6): red bold
• Moderate (0.3-0.6): yellow
• Loose (< 0.3): green