fix(ui): routines list — border the group headers, leave items borderless (PAP-10748)

Follow-up to feedback: the whole-group card put a border around the items.
Per the clarification ("borders around the group headers, no border around
the items"), drop the enclosing card border and instead border just the
group header as its own rounded box; routine rows render with no border at
all (no enclosure, no dividers).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

ui/src/pages/Routines.tsx

@@ -899,12 +899,11 @@ export function Routines() {
                           : [...routineViewState.collapsedGroups, group.key],
                       });
                     }}
-                    className="overflow-hidden rounded-lg border border-border"
                   >
                     {group.label ? (
                       <div
-                        className={`flex items-center gap-2 px-3 py-2${
-                          isOpen ? " border-b border-border" : ""
+                        className={`flex items-center gap-2 rounded-lg border border-border px-3 py-2${
+                          isOpen ? " mb-1" : ""
                         }`}
                       >
                         <CollapsibleTrigger className="flex items-center gap-1.5">

ui/storybook/stories/routines-list-groups.stories.tsx

@@ -54,10 +54,9 @@ function GroupedList() {
               onOpenChange={(open) =>
                 setCollapsed((prev) => (open ? prev.filter((k) => k !== group.key) : [...prev, group.key]))
               }
-              className="overflow-hidden rounded-lg border border-border"
             >
               {group.label ? (
-                <div className={`flex items-center gap-2 px-3 py-2${isOpen ? " border-b border-border" : ""}`}>
+                <div className={`flex items-center gap-2 rounded-lg border border-border px-3 py-2${isOpen ? " mb-1" : ""}`}>
                   <CollapsibleTrigger className="flex items-center gap-1.5">
                     <ChevronRight className="h-3.5 w-3.5 shrink-0 text-muted-foreground transition-transform [[data-state=open]>&]:rotate-90" />
                     <span className="text-sm font-semibold uppercase tracking-wide">{group.label}</span>