chore(changeset): declare Clause-② yes (widening) for #29961

The PR adds published @objectstack/objectql exports (the stored-expression
backfill functions and types), one public method
ObjectQL.computeStoredExpressionsOver and a new CLI command; nothing
narrows. The dispatch order proposed `no`; corrected on the seat's
review, as #30183 declared the same shape.

Claude-Session: https://claude.ai/code/session_01Utp6Cb2FL7H75wB1wA6PpZ
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

.changeset/29961-stored-expression-backfill.md

@@ -5,7 +5,7 @@
 
 fix(objectql,cli): `os migrate stored-expressions` fills a stored computed field on rows stored before it was declared, and the boot names the command when a sample of rows needs it
 
-Clause-②: no
+Clause-②: yes (widening)
 Metadata-protocol: none
 
 A stored computed field (a non-`formula` field declaring `expression`) is computed by the engine on every insert and update and on nothing else, so declaring one on an object that already holds rows left the new column NULL on every existing row until each was next written; a filter, sort, roll-up or analytics anchor over it read NULL where the expression gives a value, with no error. A fresh database was right and an upgraded one was not.