Rename internal helpers and adjust related calls

Rename `structure` to `s` in Structures and `unit` to `u` in Units,
updating all
call sites. Refactor `Structures::text` to match on the owner directly
and
push the owner line only for claimed owners. Change the “% )” token
color
in unit display from green to gray.

src/app/states/skirmish_states/units/unit_trait.rs

@@ -40,7 +40,7 @@ pub trait Unit {
                 max_hp.green(),
                 " ( ".gray(),
                 hp_percent.green(),
-                "% )".green(),
+                "% )".gray(),
             ]),
         ]);