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/shared/lib/storybook/index.ts

@@ -1,9 +1,5 @@
 /**
- * ============================================================================
- * STORYBOOK HELPERS
- * ============================================================================
- *
- * Helper components and utilities for Storybook stories.
+ * Storybook helpers: components and utilities for stories.
  *
  * ## Usage
  *

src/shared/ui/ComboControl/ComboControl.svelte

@@ -84,9 +84,11 @@ const displayLabel = $derived(label ?? controlLabel ?? '');
             {formattedValue()}
         </span>
     </div>
-
-    <!-- ── FULL MODE ──────────────────────────────────────────────────────────────── -->
 {:else}
+    <!--
+        FULL MODE
+        +/- buttons flanking a slider popover.
+    -->
     <div class={cn('flex items-center px-1 relative', className)}>
         <!-- Decrease button -->
         <Button

src/shared/ui/SidebarContainer/SidebarContainer.svelte

@@ -43,7 +43,7 @@ function close() {
 
 {#if responsive.isMobile}
     <!--
-        ── MOBILE: fixed overlay ─────────────────────────────────────────────
+        MOBILE: fixed overlay.
         Only rendered when open. Both backdrop and panel use Svelte transitions
         so they animate in and out independently.
     -->
@@ -70,7 +70,7 @@ function close() {
     {/if}
 {:else}
     <!--
-        ── DESKTOP: collapsible column ───────────────────────────────────────
+        DESKTOP: collapsible column.
         Always in the DOM — width transitions between 320px and 0.
         overflow-hidden clips the w-80 inner div during the collapse.