resource_control: add privilege requirement for dashboard capacity es…

…timation (#18082) (#18088)

dashboard/dashboard-resource-manager.md

@@ -63,6 +63,10 @@ Before resource planning, you need to know the overall capacity of the cluster.
 
   You can select an appropriate time range using **CPU Usage** in the [Metrics](#metrics) section.
 
+> **Note:**
+>
+> To use the capacity estimation feature, the current login user must have the `SUPER` or `RESOURCE_GROUP_ADMIN` privilege and the `SELECT` privilege for some system tables. Before using this feature, ensure the current user has these privileges. Otherwise, some features might not work properly. For more information, see [`CALIBRATE RESOURCE`](/sql-statements/sql-statement-calibrate-resource.md#privileges).
+
 ## Metrics
 
 By observing the metrics on the panels, you can understand the current overall resource consumption status of the cluster. The monitoring metrics and their meanings are as follows:

sql-statements/sql-statement-calibrate-resource.md

@@ -28,7 +28,7 @@ To execute this command, make sure that the following requirements are met:
 
 - You have enabled [`tidb_enable_resource_control`](/system-variables.md#tidb_enable_resource_control-new-in-v660).
 - The user has `SUPER` or `RESOURCE_GROUP_ADMIN` privilege.
-- The user has the `SELECT` privilege for all tables in the `METRICS_SCHEMA` schema.
+- To [estimate capacity based on actual workload](#estimate-capacity-based-on-actual-workload), the user must have the `SELECT` privilege for all tables in the `METRICS_SCHEMA` schema.
 
 ## Methods for estimating capacity