br: pitr restore mode (#21254)

Author: Leavrth

br/br-pitr-guide.md

@@ -117,6 +117,8 @@ Restore KV Files <--------------------------------------------------------------
 *** ["restore log success summary"] [total-take=xxx.xx] [restore-from={TS}] [restore-to={TS}] [total-kv-count=xxx] [total-size=xxx]
 ```
 
+During data restore, the table mode of the target table is automatically set to `restore`. Tables in `restore` mode do not allow any read or write operations. After data restore is complete, the table mode automatically switches back to `normal`, and you can read and write the table normally. This mechanism ensures task stability and data consistency throughout the restore process.
+
 ## Clean up outdated data
 
 As described in the [Usage Overview of TiDB Backup and Restore](/br/br-use-overview.md):

br/br-snapshot-guide.md

@@ -103,6 +103,8 @@ Restore Pipeline <--------------------------------------------------------------
 *** ["Full Restore success summary"] [total-ranges=20] [ranges-succeed=20] [ranges-failed=0] [merge-ranges=7.546971ms] [split-region=343.594072ms] [restore-files=1.57662s] [default-CF-files=6] [write-CF-files=14] [split-keys=9] [total-take=4.344617542s] [total-kv=5] [total-kv-size=327B] [average-speed=75.27B/s] [restore-data-size(after-compressed)=4.813kB] [Size=4813] [BackupTS=435844901803917314]
 ```
 
+During data restore, the table mode of the target table is automatically set to `restore`. Tables in `restore` mode do not allow any read or write operations. After data restore is complete, the table mode automatically switches back to `normal`, and you can read and write the table normally. This mechanism ensures task stability and data consistency throughout the restore process.
+
 ### Restore a database or a table
 
 BR supports restoring partial data of a specified database or table from backup data. This feature allows you to filter out unwanted data and back up only a specific database or table.