core&ui: contest correction mode

packages/ui-default/pages/contest.page.styl

@@ -110,7 +110,7 @@ $highlight-button-color = #F6DF45
         width: auto
 
 .page--contest_problemlist
-  .col--status
+  .col--status, .col--correction
     width: rem(150px)
 
   .col--submit-at
@@ -128,7 +128,7 @@ $highlight-button-color = #F6DF45
     border-left: 1px solid $table-border-color
 
   +mobile()
-    .col--submit-at
+    .col--submit-at, .col--correction
       display: none
 
   +tablet()