fix(frontend): storage failures use the error colour next to the warning, shared mark on its own line in the list, trash key is visible

frontend/src/lib/styles/dark-theme.scss

@@ -5,6 +5,7 @@ html.theme-dark {
   --color-storage-audio: #c98500;
   --color-storage-other: #3987e5;
   --color-storage-warning: #fb8c00;
+  --color-storage-trash: #6c6c6c;
   --storage-tile-mix: 90%;
   --color-primary: #8774e1;
   --color-primary-opacity: #8378db1e;

frontend/src/lib/styles/variables.scss

@@ -139,6 +139,7 @@
     --color-storage-audio: #a36a00;
     --color-storage-other: #2a78c8;
     --color-storage-warning: #a85a00;
+    --color-storage-trash: #939799;
     --storage-tile-mix: 100%;
 
     --color-yellow: #{$color-yellow};