docs: remove decorative separator comments

Strip box-drawing (──) section dividers and ===/banner headers — visual
noise with no information. Where a divider label carried a non-obvious
why (VirtualList owns scrolling; mobile footer is md:hidden because header
stats take over) it is kept as a plain one-line comment; pure restatements
of the markup (Header bar, Red hover line, Bottom: fixed controls) are
dropped. Single comment style, no fluff.

src/widgets/ComparisonView/ui/Sidebar/Sidebar.svelte

@@ -52,7 +52,6 @@ const side = $derived<Side>(comparisonStore.side);
         className,
     )}
 >
-    <!-- ── Header: title + A/B toggle ────────────────────────────────── -->
     <div
         class="
             p-6 shrink-0
@@ -96,14 +95,13 @@ const side = $derived<Side>(comparisonStore.side);
         </ButtonGroup>
     </div>
 
-    <!-- ── Main: content area (no scroll - VirtualList handles scrolling) ─────────────────────────────── -->
+    <!-- No scroll here; VirtualList handles scrolling -->
     <div class="flex-1 min-h-0 surface-canvas">
         {#if main}
             {@render main()}
         {/if}
     </div>
 
-    <!-- ── Bottom: fixed controls ─────────────────────────────────────── -->
     {#if controls}
         <div
             class="