chore: naming trusted domain (#11384)

# Which Problems Are Solved

As part of the consistent naming effort, this PR focuses on "Trusted
Domains".

# How the Problems Are Solved

- All terms referring to a domain that is used in API responses were
changed to "Trusted Domain" or "trusted domain".

# Additional Changes

None

# Additional Context

- closes #11297

---------

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

docs/docs/guides/integrate/login-ui/login-app.mdx

@@ -119,7 +119,7 @@ In order to run the new Login app, make sure to follow the instructions in the [
 #### How to setup domains for OIDC
 
 When setting up the new Login app for OIDC, the domain must be registered on your instance and use https.
-To register your login domain on your instance, [add](/docs/apis/resources/admin/admin-service-add-instance-trusted-domain) your domain on your instances trusted domains.
+To register your login domain on your instance, [add](/docs/apis/resources/admin/admin-service-add-instance-trusted-domain) your domain on your instances Trusted Domains.
 
 #### OIDC Proxy
 
@@ -140,7 +140,7 @@ You can review an example implementation of a middleware [here](https://github.c
 To deploy your own version on Vercel, navigate to your instance and create a service user.
 Create a personal access token (PAT) for the user and copy and set it as `ZITADEL_SERVICE_USER_TOKEN`, then navigate to Default settings and make sure it gets `IAM_LOGIN_CLIENT` permissions.
 Finally set your instance url as `ZITADEL_API_URL`. Make sure to set it without trailing slash.
-Also ensure your login domain is registered on your instance by adding it as a [trusted domain](/docs/apis/resources/admin/admin-service-add-instance-trusted-domain).
+Also ensure your login domain is registered on your instance by adding it as a [Trusted Domain](/docs/apis/resources/admin/admin-service-add-instance-trusted-domain).
 
 If you want to enforce users to have their email verified, you can set the optional `EMAIL_VERIFICATION` variable to `true` in your environment and your users will be enforced to verify their email address before they can log in.
 

docs/docs/guides/integrate/login/hosted-login.mdx

@@ -186,7 +186,7 @@ You can also activate the v2 login for your apps, so users are redirected to `/u
         4. If you have used the deploy button in the steps before, you will automatically be asked for this step. Enter the environment variables in Vercel
            - PAT
            - ZITADEL_API_URL (Example: https://my-domain.zitadel.cloud, no trailing slash)
-        5. Add the domain where your login UI is hosted to the [trusted domains](https://zitadel.com/docs/apis/resources/admin/admin-service-add-instance-trusted-domain) in Zitadel. (Example: my-new-zitadel-login.vercel.app)
+        5. Add the domain where your login UI is hosted to the [Trusted Domains](https://zitadel.com/docs/apis/resources/admin/admin-service-add-instance-trusted-domain) in Zitadel. (Example: my-new-zitadel-login.vercel.app)
         6. Use the new login in your application.
             <PreventLockout/>
             You have three different options on how to achieve this:

docs/sidebars.js

@@ -1094,7 +1094,7 @@ module.exports = {
                 title: "Instance Service API",
                 slug: "/apis/resources/instance_service_v2",
                 description:
-                  "This API is intended to manage instances, Custom Domains and trusted domains in ZITADEL.\n" +
+                  "This API is intended to manage instances, Custom Domains and Trusted Domains in ZITADEL.\n" +
                   "\n" +
                   "This v2 of the API provides the same functionalities as the v1, but organised on a per resource basis.\n" +
                   "The whole functionality related to domains (custom and trusted) has been moved under this instance API."