fix(ui): address PR-Agent feedback on health redesign

PR-Agent flagged two real bugs at score 84:

1. Accessibility (HealthPriorityCard): the priority card header was a
   clickable <div> with onClick, making expand/collapse mouse-only.
   Promote it to a <button type="button"> with aria-expanded reflecting
   state and a contextual aria-label, and a focus-visible ring. The
   inner content is extracted into a shared fragment so the button and
   the no-content fallback <div> render the same markup.

2. Time display (HealthStatusRibbon): formatRelativeTime lost the hours
   branch from the original health.tsx, so a 2-hour-old scan showed as
   '120 minutes ago' instead of '2 hours ago'. Restore the hours
   rollover with health.hoursAgo i18n key.

ui/src/components/health/health-priority-card.tsx

@@ -35,6 +35,39 @@ export function HealthPriorityCard({ check }: HealthPriorityCardProps) {
     }
   };
 
+  const headerInner = (
+    <>
+      {/* Status Icon with Ring */}
+      <div
+        className={cn(
+          'flex items-center justify-center w-12 h-12 rounded-2xl shrink-0',
+          isError ? 'bg-rose-500/10 text-rose-500' : 'bg-amber-500/10 text-amber-500'
+        )}
+      >
+        <Icon className="w-6 h-6" />
+      </div>
+
+      <div className="flex-1 min-w-0 space-y-1">
+        <div className="flex items-center justify-between">
+          <h3 className="text-lg font-bold tracking-tight">{check.name}</h3>
+          {hasContent && (
+            <div className="p-1 hover:bg-muted rounded-full transition-colors">
+              <ChevronRight
+                className={cn(
+                  'w-5 h-5 text-muted-foreground transition-transform',
+                  isExpanded && 'rotate-90'
+                )}
+              />
+            </div>
+          )}
+        </div>
+        <p className="text-sm font-medium leading-relaxed text-muted-foreground/80">
+          {check.message}
+        </p>
+      </div>
+    </>
+  );
+
   return (
     <motion.div
       layout
@@ -53,39 +86,27 @@ export function HealthPriorityCard({ check }: HealthPriorityCardProps) {
         <div className="absolute inset-0 rounded-[calc(2rem-1px)] shadow-[inset_0_1px_1px_rgba(255,255,255,0.1)] pointer-events-none" />
 
         <div className="p-6">
-          <div
-            className={cn('flex items-start gap-4', hasContent && 'cursor-pointer select-none')}
-            onClick={() => hasContent && setIsExpanded(!isExpanded)}
-          >
-            {/* Status Icon with Ring */}
-            <div
-              className={cn(
-                'flex items-center justify-center w-12 h-12 rounded-2xl shrink-0',
-                isError ? 'bg-rose-500/10 text-rose-500' : 'bg-amber-500/10 text-amber-500'
-              )}
+          {/*
+           * Header acts as the expand/collapse trigger when there's
+           * additional content (details, fix, fixable). Render as <button>
+           * so keyboard and screen-reader users can toggle it; aria-expanded
+           * reflects state. Without content, render a plain <div>.
+           */}
+          {hasContent ? (
+            <button
+              type="button"
+              onClick={() => setIsExpanded(!isExpanded)}
+              aria-expanded={isExpanded}
+              aria-label={
+                isExpanded ? `Collapse ${check.name} details` : `Expand ${check.name} details`
+              }
+              className="flex w-full select-none items-start gap-4 rounded-2xl text-left focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 focus-visible:ring-offset-background"
             >
-              <Icon className="w-6 h-6" />
-            </div>
-
-            <div className="flex-1 min-w-0 space-y-1">
-              <div className="flex items-center justify-between">
-                <h3 className="text-lg font-bold tracking-tight">{check.name}</h3>
-                {hasContent && (
-                  <div className="p-1 hover:bg-muted rounded-full transition-colors">
-                    <ChevronRight
-                      className={cn(
-                        'w-5 h-5 text-muted-foreground transition-transform',
-                        isExpanded && 'rotate-90'
-                      )}
-                    />
-                  </div>
-                )}
-              </div>
-              <p className="text-sm font-medium leading-relaxed text-muted-foreground/80">
-                {check.message}
-              </p>
-            </div>
-          </div>
+              {headerInner}
+            </button>
+          ) : (
+            <div className="flex w-full items-start gap-4">{headerInner}</div>
+          )}
 
           <AnimatePresence>
             {isExpanded && (

ui/src/components/health/health-status-ribbon.tsx

@@ -25,7 +25,11 @@ function formatRelativeTime(
   const seconds = Math.floor((Date.now() - timestamp) / 1000);
   if (seconds < 5) return t('health.justNow');
   if (seconds < 60) return t('health.secondsAgo', { count: seconds });
-  return t('health.minutesAgo', { count: Math.floor(seconds / 60) });
+  const minutes = Math.floor(seconds / 60);
+  if (minutes < 60) return t('health.minutesAgo', { count: minutes });
+  // Roll up to hours so a stale "120 minutes ago" reads as "2 hours ago"
+  const hours = Math.floor(minutes / 60);
+  return t('health.hoursAgo', { count: hours });
 }
 
 export function HealthStatusRibbon({