fix: correct grammar and standardize Zitadel branding

Author: mridang

.devcontainer/devcontainer.json

@@ -1,5 +1,5 @@
 {
-  "name": "ZITADEL Example Qwik Auth",
+  "name": "Zitadel Example Qwik Auth",
   "image": "mcr.microsoft.com/devcontainers/javascript-node:22-bookworm",
   "forwardPorts": [3000],
   "portsAttributes": {

src/routes/index.tsx

@@ -19,7 +19,7 @@ export default component$(() => {
                 PKCE Authentication Demo
               </h1>
               <p class="mb-8 text-xl text-gray-600">
-                This application demonstrates an PKCE authentication flow with
+                This application demonstrates a PKCE authentication flow with
                 Zitadel. Perfect for learning OAuth 2.0 security patterns and
                 integrating with your own application.
               </p>