cloud: add cloud release notes for release-20260526

tidb-cloud/releases/tidb-cloud-release-notes.md

@@ -8,6 +8,37 @@ aliases: ['/tidbcloud/supported-tidb-versions','/tidbcloud/release-notes']
 
 This page lists the release notes of [TiDB Cloud](https://www.pingcap.com/tidb-cloud/) in 2026.
 
+## May 26, 2026
+
+**General changes**
+
+- **TiDB Cloud Starter**
+
+    - Add two new AWS regions for [full-text search](https://docs.pingcap.com/ai/vector-search-full-text-search-python/) (public preview) on [TiDB Cloud Starter](/tidb-cloud/select-cluster-tier.md#starter): `Tokyo (ap-northeast-1)` and `Oregon (us-west-2)`. The feature is now available in the following AWS regions:
+
+        - `Tokyo (ap-northeast-1)`
+        - `Oregon (us-west-2)`
+        - `Frankfurt (eu-central-1)`
+        - `Singapore (ap-southeast-1)`
+
+- **TiDB Cloud Essential**
+
+    - Top RU is now available in public preview for [TiDB Cloud Essential](/tidb-cloud/select-cluster-tier.md#essential) in the following regions:
+
+        - AWS: `Oregon (us-west-2)`, `Frankfurt (eu-central-1)`, `Singapore (ap-southeast-1)`
+
+      This feature shows the top RU-consuming SQL statements at minute-level granularity, helping you quickly identify resource-intensive queries to reduce costs.
+
+      The feature is rolling out in phases. To request early access, contact [support@pingcap.com](mailto:support@pingcap.com).
+
+**API changes**
+
+- TiDB Cloud IAM API (v1beta1) supports managing organization members programmatically.
+
+    The new `/members` endpoints let you manage organization membership and role assignments. You can use these endpoints to automate user lifecycle management tasks, such as onboarding new members with specific roles, adjusting permissions as responsibilities change, and removing members who leave the organization.
+
+    For more information, see [TiDB Cloud IAM API](https://docs.pingcap.com/tidbcloud/api/v1beta1/iam/#tag/Member).
+
 ## May 19, 2026
 
 **General changes**