docs: Quickstart add frameworks (#11485)

# Which Problems Are Solved

The quickstart only shows the steps to take to get a working zitadel
login into your app with react.
For users with another framework or languages we didn't show how to get
to success fast.

# How the Problems Are Solved

- Adding different frameworks to the qucisktart example
- Make sure the app configurations in the onboarding flow from the
console match the configurations from the examples
- Docs link in console onboarding flow point towards quickstart
- Quickstart accepts framework selector, to pre select a framework from
another page

---------

Co-authored-by: Federico Coppede <[email protected]>
Co-authored-by: Copilot <[email protected]>

apps/docs/content/guides/start/_app_config.mdx

@@ -0,0 +1,18 @@
+export default function AppConfig({ redirectUrl, postLogoutRedirectUrl }) {
+    return (
+        <div>
+            <ul>
+                <li>
+                    <b>Auth Strategy</b>: <a href="/docs/apis/openidoauth/grant-types#authorization-code">Authorization Code Flow (PKCE)</a>. This modern standard ensures tokens are exchanged securely without needing a client secret in your frontend.
+                </li>
+                <li><b>Redirect URIs</b>: These define where users return after authentication:
+                    <ul>
+                        <li>Redirect URI: {redirectUrl} (Landing page after login)</li>
+                        <li>Post Logout URI: {postLogoutRedirectUrl} (Landing page after logout)</li>
+                    </ul>
+                </li>
+            </ul>
+        </div>
+
+);
+}