Refactor admin pages to use shared head and navigation components

- Created `admin-head.php` for consistent <head> markup across admin pages.
- Created `admin-nav.php` for shared navigation bar, reducing duplication.
- Updated all admin pages (account, hours, index, login, menu, users) to utilize the new components.
- Added security headers to `auth.php` and `index.php` for improved security.
- Introduced `security-headers.php` to manage security headers across the application.
- Moved inline styles from admin pages to SCSS files to comply with Content Security Policy (CSP).
- Normalized file permissions during build process to prevent permission issues on deployment.

admin/account.php

@@ -3,6 +3,8 @@ declare(strict_types=1);
 
 require_once __DIR__ . '/../inc/auth.php';
 require_once __DIR__ . '/../inc/assets.php';
+require_once __DIR__ . '/../inc/admin-head.php';
+require_once __DIR__ . '/../inc/admin-nav.php';
 require_once __DIR__ . '/../inc/users.php';
 
 // Any signed-in user can change their own username and/or password here,
@@ -80,46 +82,17 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
 }
 
 $justSaved = !$_POST && isset($_GET['saved']);
-$isAdmin = ($user['role'] ?? '') === 'admin';
 // After a failed save, keep the username they typed in the field.
 $usernameValue = $_POST ? trim(account_post_str('username')) : $user['username'];
 ?>
 <!doctype html>
 <html lang="en">
 
-<head>
-	<meta charset="UTF-8">
-	<meta name="viewport" content="width=device-width, initial-scale=1">
-	<title>My Account | The Old Fitz Admin</title>
-	<link rel="preconnect" href="https://fonts.googleapis.com">
-	<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
-	<link href="https://fonts.googleapis.com/css2?family=Fraunces:ital,opsz,wght@0,9..144,400;0,9..144,600;1,9..144,400&family=Karla:wght@400;500;600;700&family=IBM+Plex+Mono:wght@400;500&display=swap" rel="stylesheet">
-	<link rel="stylesheet" href="../styles.css<?= asset_version('styles.css') ?>">
-</head>
+<?php render_admin_head('My Account'); ?>
 
 <body>
 
-	<nav class="admin-nav">
-		<div class="container admin-nav-inner">
-			<a href="index.php" class="admin-brand">
-				<img src="../assets/knot.png" alt="" class="knot">
-				<span>The Old Fitz Admin</span>
-			</a>
-			<div class="admin-nav-links">
-				<a href="index.php">Announcements</a>
-				<a href="menu.php">Menu</a>
-				<?php if ($isAdmin): ?>
-				<a href="users.php">Users</a>
-				<?php endif; ?>
-				<a href="hours.php">Hours</a>
-			</div>
-			<div class="admin-user">
-				<a href="../" target="_blank" rel="noopener">View Public Site ↗</a>
-				<a href="account.php" class="admin-account-link active" title="My Account"><?= htmlspecialchars($user['username']) ?></a>
-				<a href="logout.php">Sign Out</a>
-			</div>
-		</div>
-	</nav>
+	<?php render_admin_nav($user, 'account'); ?>
 
 	<main class="dashboard-layout">
 		<div class="container">