feat: add app icon branding to all remaining page headers

- CalendarView header now displays icon
- ReflectionsList header now displays icon
- AnsweredPrayers header now displays icon
- ThingsToPrayFor header now displays icon

Completes visual identity unification across all main screens

src/components/ReminderBanner.tsx

@@ -1,6 +1,7 @@
 'use client';
 
 import React, { useState, useEffect } from 'react';
+import { BellRing, X } from 'lucide-react';
 
 interface ReminderBannerProps {
   userEmail?: string;
@@ -58,7 +59,7 @@ export default function ReminderBanner({ userEmail }: ReminderBannerProps) {
     <div className="fixed top-0 left-0 right-0 z-40 p-4">
       <div className="max-w-md mx-auto bg-gradient-to-r from-blue-600 to-blue-500 rounded-lg shadow-lg p-4 animate-in slide-in-from-top">
         <div className="flex items-start gap-3">
-          <div className="text-2xl mt-1">🙏</div>
+          <BellRing className="w-6 h-6 text-white mt-1" />
           <div className="flex-1">
             <h3 className="font-semibold text-white">Time to Pray</h3>
             <p className="text-blue-100 text-sm mt-1">
@@ -69,7 +70,7 @@ export default function ReminderBanner({ userEmail }: ReminderBannerProps) {
             onClick={() => setShowBanner(false)}
             className="text-blue-200 hover:text-white transition-colors mt-1"
           >
-            ✕
+            <X className="w-5 h-5" />
           </button>
         </div>
         <div className="mt-3 flex gap-2">