refs ENG-661
Fixes a long-standing issue where an outdated Lexical schema in the
database triggered the unsaved changes confirmation dialog incorrectly.
Implemented a secondary hidden Lexical instance that loads the state
from the database, renders it, and uses this updated state to compare
with the live editor's scratch.
This ensures the unsaved changes prompt appears only when there are real
changes from the user.
c8ba9e8027