A document-mode plugin under packages/plugin-dev/document-mode/ that
renders the active work context's tasks as an editable TipTap document.
Per-context doc state is persisted as a last-writer-wins JSON blob via
PluginAPI.persistDataSynced; task identity (title, done state, hierarchy)
stays in NgRx and is reached through PluginAPI.updateTask and the
ANY_TASK_UPDATE hook.
It registers a work-context header button and embeds itself into the
work-view embed slot added in the preceding commit. See
docs/plans/2026-05-21-document-mode-tiptap-plugin.md for the full design.
Squashed from the feat/doc-mode-v4 work; full per-step history is
preserved in the archive/doc-mode-v4-full-history branch and the
doc-mode-v4-pre-squash tag.
