docs: create guide for generic OIDC IDP (#11233)

Fixes #7191

docs/docs/guides/integrate/identity-providers/generic-oidc.mdx

@@ -0,0 +1,68 @@
+---
+title: Configure a Generic OIDC Identity Provider in ZITADEL
+sidebar_label: Generic OIDC
+id: generic-oidc
+---
+
+import GeneralConfigDescription from './_general_config_description.mdx';
+import Intro from './_intro.mdx';
+import CustomLoginPolicy from './_custom_login_policy.mdx';
+import IDPsOverview from './_idps_overview.mdx';
+import Activate from './_activate.mdx';
+import PrefillAction from './_prefill_action.mdx';
+import TestSetup from './_test_setup.mdx';
+
+<Intro provider="your OIDC Provider"/>
+
+## Open the Generic OIDC Provider Template
+
+<IDPsOverview templates="Generic OIDC"/>
+
+Click on the ZITADEL Callback URL to copy it to your clipboard.
+You will have to paste this URL in your external OIDC provider's application configuration later.
+
+![Generic OIDC Provider](/img/guides/zitadel_generic_oidc_create_provider.png)
+
+## OIDC Provider Configuration
+
+### Register a new client/application
+
+1. Log in to your external OIDC Provider's dashboard or management console.
+2. Navigate to the applications, clients, or integrations section (name may vary depending on your provider).
+3. Create a new application or client and select "OIDC" or "OpenID Connect" as the type.
+4. Set a name for the application.
+5. [Paste the ZITADEL Callback URL you copied before](#open-the-generic-oidc-provider-template) into the "redirect URIs" or "sign-in redirect URIs" field.
+6. Save or copy the generated **Client ID** and **Client Secret**.
+
+> The exact steps and terminology may vary for each provider. Refer to your provider's documentation if you don't see these options.
+
+## ZITADEL Configuration
+
+1. Return to [the Generic OIDC Provider template in ZITADEL](#open-the-generic-oidc-provider-template).
+2. Enter the **Client ID** and **Client Secret** from your OIDC provider's application.
+3. Give the provider a name (e.g., "My OIDC Provider"). This name will appear as a button on the ZITADEL login screen.
+4. Enter the **Issuer URL** of your OIDC provider (e.g., `https://your-provider.example.com`).
+
+You can optionally configure the following settings. ZITADEL provides sensible defaults if you leave these unchanged.
+
+**Scopes**: The scopes define which information ZITADEL will request from the provider. `openid`, `profile`, and `email` are pre-filled.
+This information is used to create or update the user within ZITADEL.
+ZITADEL ensures that at least the `openid` scope is always sent.
+
+**Use PKCE**: If enabled, Proof Key for Code Exchange (PKCE) will be used to secure the authorization code flow in addition to the client secret.
+
+<GeneralConfigDescription provider_account="OIDC provider account" />
+
+### Activate IdP
+
+<Activate/>
+
+![Activate the OIDC Provider](/img/guides/zitadel_activate_okta.png)
+
+### Ensure your Login Policy allows External IDPs
+
+<CustomLoginPolicy/>
+
+## Test the setup
+
+<TestSetup loginscreen="your OIDC provider login"/>

docs/sidebars.js

@@ -381,6 +381,7 @@ module.exports = {
             "guides/integrate/identity-providers/ldap",
             "guides/integrate/identity-providers/openldap",
             "guides/integrate/identity-providers/okta-oidc",
+            "guides/integrate/identity-providers/generic-oidc",
             "guides/integrate/identity-providers/okta-saml",
             "guides/integrate/identity-providers/keycloak",
             "guides/integrate/identity-providers/linkedin-oauth",