docs: remove obsolete cairo.sql.backup.* config keys

The old table backup feature was removed in QuestDB 9.3.2 (questdb/questdb#6558).
Remove the four cairo.sql.backup.* config keys from the configuration docs,
the BACKUP TABLE permission from the RBAC reference, and update the
SHOW PARAMETERS example that referenced cairo.sql.backup.root.

Fixes questdb/questdb#6767

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: mtopolnik

documentation/configuration/configuration-utils/_cairo.config.json

@@ -19,22 +19,6 @@
     "default": "1 second",
     "description": "The minimum size of in-memory buffer in milliseconds. The buffer is allocated dynamically through analyzing the shape of the incoming data, and `o3MinLag` is the lower limit."
   },
-  "cairo.sql.backup.root": {
-    "default": "null",
-    "description": "Output root directory for backups."
-  },
-  "cairo.sql.backup.dir.datetime.format": {
-    "default": "null",
-    "description": "Date format for backup directory."
-  },
-  "cairo.sql.backup.dir.tmp.name": {
-    "default": "tmp",
-    "description": "Name of tmp directory used during backup."
-  },
-  "cairo.sql.backup.mkdir.mode": {
-    "default": "509",
-    "description": "Permission used when creating backup directories."
-  },
   "cairo.snapshot.instance.id": {
     "default": "empty string",
     "description": "Instance id to be included into disk snapshots."

documentation/query/sql/show.md

@@ -169,8 +169,8 @@ You can optionally chain `SHOW PARAMETERS` with other clauses:
 -- This query will return all parameters where the value contains 'tmp', ignoring upper/lower case
 (SHOW PARAMETERS) WHERE value ILIKE '%tmp%';
 
--- This query will return all parameters where the property_path is not 'cairo.root' or 'cairo.sql.backup.root', ordered by the first column
-(SHOW PARAMETERS) WHERE property_path NOT IN ('cairo.root', 'cairo.sql.backup.root') ORDER BY 1;
+-- This query will return all parameters where the property_path is not 'cairo.root' or 'cairo.snapshot.instance.id', ordered by the first column
+(SHOW PARAMETERS) WHERE property_path NOT IN ('cairo.root', 'cairo.snapshot.instance.id') ORDER BY 1;
 
 -- This query will return all parameters where the value_source is 'env'
 (SHOW PARAMETERS) WHERE value_source = 'env';

documentation/security/rbac.md

@@ -565,7 +565,6 @@ SELECT * FROM all_permissions();
 | ALTER COLUMN TYPE | Database | Table | Column | Change column types |
 | ATTACH PARTITION | Database | Table | Attach partitions |
 | BACKUP DATABASE | Database | Create database backups |
-| BACKUP TABLE | Database | Table | Create table backups |
 | CANCEL ANY COPY | Database | Cancel COPY operations |
 | CREATE TABLE | Database | Create tables |
 | CREATE MATERIALIZED VIEW | Database | Create materialized views |