WebAuthn biometric + PWA widget + UI header fixes + mobile responsive

- WebAuthn: register/auth options, device management
- PWA widget page + manifest shortcuts
- Group schedule endpoint (timezones + locations)
- UI #3-#6: compact headers on tasks/calendar/projects/goals
- UI #9: mobile responsive top bars
- webauthn_credentials table

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/tasks/app/calendar/page.tsx

@@ -63,25 +63,21 @@ export default function CalendarPage() {
       extendedProps: { status: tk.status, group: tk.group_name },
     }));
 
-  // Build background events from unique groups
-  const groupColors = new Map<string, string>();
-  tasks.forEach(tk => {
-    if (tk.group_name && tk.group_color) {
-      groupColors.set(tk.group_name, tk.group_color);
-    }
-  });
-
   if (!token) return null;
 
   return (
-    <div className="p-4">
-      <h1 className="text-2xl font-bold mb-4">{t('calendar.title')}</h1>
+    <div className="pb-24 sm:pb-8 px-4 sm:px-0">
+      {/* Compact single-row header */}
+      <div className="flex items-center justify-between gap-2 mb-3">
+        <h1 className="text-xl font-bold dark:text-white truncate">{t('calendar.title')}</h1>
+      </div>
+
       {error && (
         <div className="mb-4 p-3 bg-red-50 dark:bg-red-900/20 text-red-600 dark:text-red-400 rounded-lg text-sm">
           {error}
         </div>
       )}
-      <div className="bg-white dark:bg-gray-800 rounded-xl p-4 shadow">
+      <div className="bg-white dark:bg-gray-800 rounded-xl p-2 sm:p-4 shadow calendar-compact">
         <FullCalendar
           plugins={[dayGridPlugin, timeGridPlugin, interactionPlugin]}
           initialView="timeGridWeek"