Update auth guidance for status command

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: gonzaloriestra

.changeset/brave-agents-login.md

@@ -0,0 +1,6 @@
+---
+'@shopify/cli': patch
+'@shopify/cli-kit': patch
+---
+
+Improve Shopify CLI login guidance for agent-driven authentication flows.

docs/cli/auth.md

@@ -6,17 +6,19 @@ Shopify CLI authenticates developers with Shopify through a device-code OAuth fl
 
 Shopify CLI currently supports user-driven device authentication:
 
-1. Run a command that requires authentication, or run `shopify auth login` directly.
-2. Shopify CLI prints a verification URL and user code, or opens the verification URL in your browser.
-3. The user completes login in the browser.
-4. Keep the CLI process running. It polls for completion and continues automatically after authentication succeeds.
+1. Check whether a session is already available with `shopify auth status` or `shopify auth status --json`.
+2. Run a command that requires authentication, or run `shopify auth login` directly.
+3. Shopify CLI prints a verification URL and user code, or opens the verification URL in your browser.
+4. The user completes login in the browser.
+5. Keep the CLI process running. It polls for completion and continues automatically after authentication succeeds.
 
 Agents should show the verification URL and user code to the user, ask the user to complete authentication in the browser, and wait for the CLI command to finish.
 
 ## Commands
 
 - `shopify auth login`: Start an interactive Shopify account login.
 - `shopify auth logout`: Clear the stored Shopify CLI session.
+- `shopify auth status`: Check whether Shopify CLI has a usable Shopify account session. Use `--json` for machine-readable output.
 - Commands that need authentication may start the same login flow automatically.
 
 ## Non-interactive environments