feat: add clickable step count to toggle group collapse/expand

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/lib/components/graph/GroupNodeCard.svelte

@@ -19,6 +19,7 @@
 		showNote?: boolean
 		editMode?: boolean
 		modules?: FlowModule[]
+		onExpand?: () => void
 		onSummaryUpdate?: (text: string) => void
 		onNoteUpdate?: (text: string) => void
 		onHeightChange?: (height: number) => void
@@ -34,6 +35,7 @@
 		showNote = false,
 		editMode = false,
 		modules,
+		onExpand,
 		onSummaryUpdate,
 		onNoteUpdate,
 		onHeightChange
@@ -132,7 +134,13 @@
 			>
 		{/if}
 		{#if stepCount != null}
-			<span class="text-3xs opacity-60 ml-auto shrink-0 whitespace-nowrap"
+			<!-- svelte-ignore a11y_click_events_have_key_events -->
+			<!-- svelte-ignore a11y_no_static_element_interactions -->
+			<span
+				class="text-3xs opacity-60 ml-auto shrink-0 whitespace-nowrap {onExpand
+					? 'cursor-pointer hover:opacity-100 hover:text-blue-500 dark:hover:text-blue-400'
+					: ''}"
+				onclick={onExpand ? stopPropagation(preventDefault(onExpand)) : undefined}
 				>{stepCount} node{stepCount !== 1 ? 's' : ''}</span
 			>
 		{/if}

frontend/src/lib/components/graph/GroupOverlay.svelte

@@ -155,6 +155,7 @@
 							showNote={showNotes && group.note != null}
 							{editMode}
 							modules={getGroupModules(group)}
+							onExpand={() => toggleCollapse(group.id)}
 							onSummaryUpdate={(text) => groupEditorContext?.groupEditor.updateSummary(group.id, text)}
 							onNoteUpdate={(text) => groupEditorContext?.groupEditor.updateNote(group.id, text)}
 							onHeightChange={(h) => groupEditorContext?.groupEditor.setNoteHeight(group.id, h)}

frontend/src/lib/components/graph/renderers/nodes/CollapsedGroupNode.svelte

@@ -47,6 +47,7 @@
 				showNote={data.showNotes && data.note != null}
 				editMode={data.editMode}
 				modules={data.modules}
+				onExpand={() => data.eventHandlers.expandGroup(data.groupId)}
 				onSummaryUpdate={(text) =>
 					groupEditorContext?.groupEditor.updateSummary(data.groupId, text)}
 				onNoteUpdate={(text) => groupEditorContext?.groupEditor.updateNote(data.groupId, text)}