Fix compilation errors in main.rs

[ethanbissbort]

Fixed two compilation errors reported by GitHub CI:

1. ModuleDescriptor field access errors (lines 162, 164):

   • Changed module.name() to module.name
   • Changed module.description() to module.description
   • ModuleDescriptor has fields, not methods

2. Borrow of moved value error (line 153):

   • Changed 'for module in modules' to 'for module in &modules'
   • Prevents moving modules vector so it can be used later for .len()

Also cleaned up unused imports:

• Removed unused cli::FluxCli import
• Removed unused error::FluxError import

Build verified:

• cargo check: ✅ No errors
• cargo build --lib: ✅ Success
• cargo build --bin flux: ✅ Success
• Only warnings remain (unused imports in other files)