Tracking issue for Harper support in word processors and editors for non-coders

Already supported:
- Obsidian

Discussed but no issue:
- https://github.com/Automattic/harper/discussions/1760

Start with the Harper project context and the linked discussion at github.com/Automattic/harper/discussions/1760. The issue names no implementation files, tests, editor targets, or acceptance criteria, so first clarify which word processors or editors are in scope and what support would mean; done cannot be determined from the current description.

Written by the indexing model from the issue text.