feat(backend): Add preferredSignInStrategyWhenPasswordRequired (#8878)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: dmoerner

.changeset/instance-preferred-sign-in-strategy.md

@@ -0,0 +1,5 @@
+---
+'@clerk/backend': minor
+---
+
+Add support for the `preferredSignInStrategyWhenPasswordRequired` parameter to `clerkClient.instance.update()`. Accepts `'password'` or `'otp'` to override the preferred sign-in strategy when a password is required, or an empty string to clear the override.

packages/backend/src/api/endpoints/InstanceApi.ts

@@ -36,6 +36,12 @@ type UpdateParams = {
    * Whether the instance should use URL-based session syncing in development mode (i.e. without third-party cookies).
    */
   urlBasedSessionSyncing?: boolean | null | undefined;
+  /**
+   * Overrides the sign-in strategy that is preferred when a password is required.
+   *
+   * @remarks Accepts `'password'` or `'otp'`. Pass an empty string to clear the override. Passing `null` or `undefined` leaves the current value unchanged. The value is only consulted when a password is required, and is dormant otherwise.
+   */
+  preferredSignInStrategyWhenPasswordRequired?: 'password' | 'otp' | '' | null | undefined;
 };
 
 type UpdateRestrictionsParams = {