Main advanced to @Database v15 (the #66 folder hierarchyDelimiter
migration). Renumbered the account-tables-drop migration 14->15 to
15->16 and bumped the cache DB to v16; this exports the v16 schema
(main's v15 delimiter schema minus the moved account tables). Main's
own 15.json is kept unchanged.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>