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/ui/editable-card.tsx

@@ -56,7 +56,7 @@ export function EditableCard({
               onClick={() => setIsEditing(true)}
               className={cn(
                 'h-7 gap-1.5 text-xs',
-                !alwaysShowEdit && 'opacity-0 group-hover:opacity-100 transition-opacity'
+                !alwaysShowEdit && 'sm:opacity-0 sm:group-hover:opacity-100 transition-opacity'
               )}
             >
               <Pencil className="h-3 w-3" />

src/components/ui/inline-editable-text.tsx

@@ -171,7 +171,7 @@ export function InlineEditableText({
           <span className={cn(!value && 'text-muted-foreground italic')}>
             {value || placeholder}
           </span>
-          <Pencil className="h-3 w-3 shrink-0 opacity-0 group-hover:opacity-50 transition-opacity" />
+          <Pencil className="h-3 w-3 shrink-0 opacity-30 sm:opacity-0 sm:group-hover:opacity-50 transition-opacity" />
         </motion.button>
       )}
     </AnimatePresence>