Dig marks in the colour of the master who set them; every master's dungeon is lit

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/rival.rs

@@ -447,6 +447,22 @@ mod tests {
         assert!(g.torches.iter().any(|t| g.map.t[t.wall].owner == owner || g.map.t[t.wall].solid()), "torches");
     }
 
+    #[test]
+    fn ai_dig_marks_carry_the_masters_side() {
+        let mut g = rival_game(1);
+        let side = g.rivals[0].side;
+        for _ in 0..(40 * 20) {
+            g.update(0.05);
+        }
+        assert!(g.map.t.iter().any(|t| t.marked && t.mark_by == side), "the AI marks in its own colour");
+        let back = crate::save::from_bytes(crate::save::to_json(&g).as_bytes()).ok().expect("loads").game;
+        assert_eq!(
+            back.map.t.iter().filter(|t| t.marked && t.mark_by == side).count(),
+            g.map.t.iter().filter(|t| t.marked && t.mark_by == side).count(),
+            "kept in the save"
+        );
+    }
+
     #[test]
     fn beating_the_rival_wins_the_free_game() {
         let mut g = rival_game(1);