Align escape warning button with code lines

Add .lines-escape to shared .lines-num/.lines-code rule so it gets the
same font-size, line-height, and vertical-align. Add horizontal padding
to the warning emoji pseudo-element.

Co-Authored-By: Claude (Opus 4.6) <noreply@anthropic.com>

web_src/css/base.css

@@ -686,6 +686,7 @@ overflow-menu .ui.label {
 }
 
 .lines-num,
+.lines-escape,
 .lines-code {
   font-size: 12px;
   font-family: var(--fonts-monospace);

web_src/css/review.css

@@ -19,6 +19,7 @@
   visibility: visible;
   content: "⚠️";
   font-family: var(--fonts-emoji);
+  padding: 0 2px;
   color: var(--color-red);
 }