fix: center update metric separators

Place both metric separators in identical fixed-width grid columns and center them explicitly so size, speed, and ETA maintain balanced spacing.

renderer/styles.css

@@ -2527,9 +2527,9 @@ select.hs-input { max-width: none; width: auto; min-width: 140px; }
 #updateProgressDetails {
   min-width: 0;
   display: grid;
-  grid-template-columns: 19ch auto 11ch auto 10ch;
+  grid-template-columns: 19ch 2ch 11ch 2ch 10ch;
   align-items: baseline;
-  gap: 5px;
+  column-gap: 0;
   color: var(--text-dim);
   font-size: 11px;
   font-variant-numeric: tabular-nums;
@@ -2542,7 +2542,8 @@ select.hs-input { max-width: none; width: auto; min-width: 140px; }
 }
 
 .update-progress-separator {
-  text-align: center;
+  display: grid;
+  place-items: center;
 }
 
 #updateProgressSpeed,