Added admin-only page, and updated server backend to actually work with

admin stuff (IsAdmin).

Pages/Admin.php

@@ -0,0 +1,39 @@
+<?php
+
+$PageTitle = "Admin";
+$PageSection = "Admin";
+
+
+?>
+
+<!DOCTYPE html>
+
+<html lang="en" data-palette="CatppuccinMocha">
+    <?php require __DIR__ . "/Bits/Head.php"; ?>
+
+    <body>
+        <?php require __DIR__ . "/Bits/Navbar.php"; ?>
+
+        <main class="MainContainer">
+            <h1>Admin</h1>
+
+            <p
+                id="AdminAccessMessage"
+                class="PageMessage"
+                aria-live="polite"
+            >
+                Checking admin access...
+            </p>
+
+            <div
+                id="AdminContent"
+                hidden
+            >
+                <p>
+                    Admin access verified. Garden content
+                    editors will live here.
+                </p>
+            </div>
+        </main>
+    </body>
+</html>