Handle PARTITION ID syntax in APPLY DELETED MASK command

Add check for PARTITION ID 'value' syntax when parsing ALTER TABLE
APPLY DELETED MASK IN PARTITION clause. This sets the PartitionIsID flag
so the explain output correctly shows Partition_ID instead of Partition.

Fixes test: 03743_fix_estimator_crash/stmt6

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: kyleconroy

parser/parser.go

@@ -5974,6 +5974,11 @@ func (p *Parser) parseAlterCommand() *ast.AlterCommand {
 					p.nextToken() // skip IN
 					if p.currentIs(token.PARTITION) {
 						p.nextToken() // skip PARTITION
+						// Check for PARTITION ID 'value' syntax
+						if p.currentIs(token.IDENT) && strings.ToUpper(p.current.Value) == "ID" {
+							p.nextToken()
+							cmd.PartitionIsID = true
+						}
 						cmd.Partition = p.parseExpression(LOWEST)
 					}
 				}

parser/testdata/03743_fix_estimator_crash/metadata.json

@@ -1,5 +1 @@
-{
-  "explain_todo": {
-    "stmt6": true
-  }
-}
+{}