Mobile responsiveness fixes for pipeline UI redesign

- Detail page header: stack on mobile, icon-only Advanced button on small screens
- InlineEditableText: show pencil icon on mobile (not hover-only)
- EditableCard: show Edit button on mobile (not hover-only)
- PipelineFlowchart: add right-edge fade gradient as scroll hint on mobile
- Summary cards: always 3-col grid (compact on mobile)
- Track switcher: add overflow-x-auto for horizontal scroll

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

src/components/admin/pipeline/pipeline-flowchart.tsx

@@ -79,8 +79,9 @@ export function PipelineFlowchart({
   return (
     <div
       ref={containerRef}
-      className={cn('overflow-x-auto rounded-lg border bg-card', className)}
+      className={cn('relative rounded-lg border bg-card', className)}
     >
+      <div className="overflow-x-auto">
       <svg
         width={totalWidth}
         height={totalHeight}
@@ -265,6 +266,11 @@ export function PipelineFlowchart({
           )
         })}
       </svg>
+      </div>
+      {/* Scroll hint gradient for mobile */}
+      {totalWidth > 400 && (
+        <div className="absolute right-0 top-0 bottom-0 w-8 bg-gradient-to-l from-card to-transparent pointer-events-none sm:hidden" />
+      )}
     </div>
   )
 }