Improve auth guidance for agents

[gonzaloriestra]

WHY are these changes introduced?

After adding shopify auth status, agents should have clear inline and documentation guidance for using the existing device auth flow. This PR builds on the status command by documenting the recommended sequence and making login output easier for agents to relay to users.

WHAT is this pull request doing?

• Adds docs/cli/auth.md to document Shopify CLI's agent-friendly device auth flow, including shopify auth status.
• Updates shopify auth login help and device auth output to tell agents to show the URL/code to the user and keep the command running.
• Adds regression coverage for the new device auth guidance.

How to test your changes?

• pnpm vitest run packages/cli-kit/src/private/node/session/device-authorization.test.ts packages/cli/src/cli/commands/auth/login.test.ts packages/cli-kit/src/public/node/session-auth-status.test.ts packages/cli/src/cli/commands/auth/status.test.ts
• pnpm --filter @shopify/cli-kit type-check && pnpm --filter @shopify/cli type-check

Checklist

• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've considered possible documentation changes
• I've considered analytics changes to measure impact
• The change is user-facing — I've identified the correct bump type (patch for bug fixes · minor for new features · major for breaking changes) and added a changeset with pnpm changeset add

[gonzaloriestra]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• Improve auth guidance for agents #7628 👈 (View in Graphite)
• Add auth status command #7629
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[github-actions]

Differences in type declarations

We detected differences in the type declarations generated by Typescript for this branch compared to the baseline ('main' branch). Please, review them to ensure they are backward-compatible. Here are some important things to keep in mind:

• Some seemingly private modules might be re-exported through public modules.
• If the branch is behind main you might see odd diffs, rebase main into this branch.

New type declarations

We found no new type declarations in this PR

Existing type declarations

packages/cli-kit/dist/public/node/session.d.ts

@@ -33,6 +33,21 @@ interface ServiceAccountInfo {
 interface UnknownAccountInfo {
     type: 'UnknownAccount';
 }
+export type AuthStatusName = 'authenticated' | 'needs_refresh' | 'not_authenticated' | 'invalid';
+export interface AuthStatus {
+    status: AuthStatusName;
+    authenticated: boolean;
+    account?: {
+        userId: string;
+        alias?: string;
+    };
+    identityFqdn?: string;
+    expiresAt?: string;
+    agentGuidance: {
+        instruction: string;
+        nextCommand?: string;
+    };
+}
 /**
  * Type guard to check if an account is a UserAccount.
  *
@@ -47,6 +62,12 @@ export declare function isUserAccount(account: AccountInfo): account is UserAcco
  * @returns True if the account is a ServiceAccount.
  */
 export declare function isServiceAccount(account: AccountInfo): account is ServiceAccountInfo;
+/**
+ * Returns the current Shopify CLI authentication status without starting a login flow.
+ *
+ * @returns The current authentication status.
+ */
+export declare function getAuthStatus(): Promise<AuthStatus>;
 /**
  * Ensure that we have a valid session with no particular scopes.
  *