one tiny cargo test workspace fix

.github/copilot-instructions.md

@@ -2,3 +2,4 @@ We work towards clean, modular, maintainable design, clear documentation... im n
 
 DRY: spawn subagents.
 Context: break those files out.
+Test: make functions easy to test.

ipjs/src/subcommands/link/mod.rs

@@ -146,7 +146,7 @@ mod tests {
 
         assert_eq!(link.operstate, Some(OperState::Up));
         assert_eq!(
-            link.address.map(|mac| mac.to_string()).as_deref(),
+            link.address.map(|mac| mac.to_string().to_ascii_lowercase()).as_deref(),
             Some("aa:bb:cc:dd:ee:ff")
         );
     }