feat: make service accounts a Premium feature (#24020)

docs/admin/users/headless-auth.md

@@ -1,31 +1,38 @@
 # Headless Authentication
 
-Headless user accounts that cannot use the web UI to log in to Coder. This is
-useful for creating accounts for automated systems, such as CI/CD pipelines or
-for users who only consume Coder via another client/API.
+> [!NOTE]
+> Creating service accounts requires a [Premium license](https://coder.com/pricing).
 
-You must have the User Admin role or above to create headless users.
+Service accounts are headless user accounts that cannot use the web UI to log in
+to Coder. This is useful for creating accounts for automated systems, such as
+CI/CD pipelines or for users who only consume Coder via another client/API. Service accounts do not have passwords or associated email addresses.
 
-## Create a headless user
+You must have the User Admin role or above to create service accounts.
+
+## Create a service account
 
 <div class="tabs">
 
 ## CLI
 
+Use the `--service-account` flag to create a dedicated service account:
+
 ```sh
 coder users create \
-  --email="coder-bot@coder.com" \
   --username="coder-bot" \
-  --login-type="none" \
+  --service-account
 ```
 
 ## UI
 
-Navigate to the `Users` > `Create user` in the topbar
+Navigate to **Deployment** > **Users** > **Create user**, then select
+**Service account** as the login type.
 
 ![Create a user via the UI](../../images/admin/users/headless-user.png)
 
 </div>
 
+## Authenticate as a service account
+
 To make API or CLI requests on behalf of the headless user, learn how to
 [generate API tokens on behalf of a user](./sessions-tokens.md#generate-a-long-lived-api-token-on-behalf-of-another-user).

docs/manifest.json

@@ -495,7 +495,8 @@
 						{
 							"title": "Headless Authentication",
 							"description": "Create and manage headless service accounts for automated systems and API integrations",
-							"path": "./admin/users/headless-auth.md"
+							"path": "./admin/users/headless-auth.md",
+							"state": ["premium"]
 						},
 						{
 							"title": "Groups \u0026 Roles",