feat(settings): add cover size settings and implement responsive cover sizing

Entire-Checkpoint: c2cea9c530e6

libs/ui/styles/_content-grid.scss

@@ -5,9 +5,12 @@
 //   @include grid.content-grid;
 //   @include grid.content-card;
 
-@mixin content-grid($min-width: 140px, $gap: 20px) {
+@mixin content-grid(
+    $min-width: var(--cover-grid-min-width, 148px),
+    $gap: var(--cover-gap, 16px)
+) {
     display: grid;
-    grid-template-columns: repeat(auto-fill, minmax($min-width, 1fr));
+    grid-template-columns: repeat(auto-fill, minmax(#{$min-width}, 1fr));
     gap: $gap;
 }