feat(frontend): add Playfair Display heading font to layout and pages

Load Playfair Display from Google Fonts via preconnect and stylesheet in root layout, then apply to h1 headings on BookingFlow, Account, and Contact pages for a consistent brand typography.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

frontend/src/lib/components/booking/BookingFlow.svelte

@@ -1422,7 +1422,7 @@
 
 <div class="mx-auto max-w-4xl p-6">
 	<div class="mb-8 text-center">
-		<h1 class="mb-2 text-3xl font-bold">Book Your Appointment</h1>
+		<h1 class="mb-2 font-['Playfair_Display'] text-4xl font-bold">Book Your Appointment</h1>
 		<p class="text-gray-600">Professional beauty treatments in a calm and friendly environment</p>
 	</div>
 

frontend/src/routes/+layout.svelte

@@ -47,6 +47,12 @@
 
 <svelte:head>
 	<link rel="icon" href={favicon} />
+	<link rel="preconnect" href="https://fonts.googleapis.com" />
+	<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin="anonymous" />
+	<link
+		href="https://fonts.googleapis.com/css2?family=Playfair+Display:ital,wght@0,400..900;1,400..900&display=swap"
+		rel="stylesheet"
+	/>
 </svelte:head>
 
 <NavBar />

frontend/src/routes/account/+page.svelte

@@ -1141,7 +1141,7 @@
 	<div class="mx-auto max-w-4xl space-y-6 p-4 pb-32">
 		<!-- Header -->
 		<div class="mb-8 text-center">
-			<h1 class="text-3xl font-bold">My Account</h1>
+			<h1 class="font-['Playfair_Display'] text-4xl font-bold">My Account</h1>
 			<p class="text-gray-600">Manage your profile, bookings, and settings</p>
 		</div>
 

frontend/src/routes/contact/+page.svelte

@@ -32,7 +32,7 @@
 </script>
 
 <section class="py-12">
-	<h1 class="mb-8 text-center text-2xl font-semibold">Contact Me</h1>
+	<h1 class="mb-8 text-center font-['Playfair_Display'] text-4xl font-bold">Contact Me</h1>
 	<div class="mx-auto grid max-w-[744px] gap-6 px-4 lg:grid-cols-2">
 		<div class="h-[376px]">
 			{#if loading}