Add partial filesystem data display for debugging

- Make filesystem display more forgiving - show partial data if available
- Will display usage% even if GB values are missing, or vice versa
- This should help identify which specific metrics aren't being populated
- Debug version to identify filesystem data population issues

dashboard/src/ui/widgets/system.rs

@@ -562,6 +562,15 @@ impl SystemWidget {
                         (Some(pct), Some(used), Some(total)) => {
                             format!("{}: {:.0}% {:.1}GB/{:.1}GB", filesystem.mount_point, pct, used, total)
                         }
+                        (Some(pct), _, Some(total)) => {
+                            format!("{}: {:.0}% —GB/{:.1}GB", filesystem.mount_point, pct, total)
+                        }
+                        (Some(pct), _, _) => {
+                            format!("{}: {:.0}% —GB/—GB", filesystem.mount_point, pct)
+                        }
+                        (_, Some(used), Some(total)) => {
+                            format!("{}: —% {:.1}GB/{:.1}GB", filesystem.mount_point, used, total)
+                        }
                         _ => format!("{}: —% —GB/—GB", filesystem.mount_point),
                     };