dashboard: the agenda reads from the top of its card

The frame centres a single reading, which is right for a gauge and wrong
for a list.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

frontend/src/components/Dashboard/widgets.tsx

@@ -441,7 +441,9 @@ function AgendaWidget({ widget }: WidgetProps) {
   }
 
   return (
-    <ul className="grid gap-1.5 text-sm">
+    // The frame centres a single reading in its card; a list reads from the
+    // top, so it takes the slack below it.
+    <ul className="mb-auto grid gap-1.5 text-sm">
       {items.map((item, index) => {
         const when = new Date(item.ts * 1000)
         return (