anotation management utilities

* full truncation of all annotations
* truncation of annotations created by cursors (i.e. not from ingestion... or should we make the ingestion annotation associate with a cursor?)
* truncation of annotations associated with a given annotator
* assignment of "respect only this version" tag to permit superceding and rolling back of annotations to particular versions. probably a view joining a on a small table I'll need to add
* propagation of annotations to associated higher/lower level entities (e.g. push gizmo up to dialogue)
* truncate annotations for a given "source" (claude, chatgpt)

No files, tests, or entry points are named. Start by decomposing the listed annotation-management operations: truncation by scope, version constraints, propagation, and source filtering. Done would require an agreed design and coverage for all requested behaviors, but the issue does not define that design or specific verification steps.

Written by the indexing model from the issue text.