task: Weekly review proposes task new/task close; tracker gains a closing write path

Files changed:
- CHANGES.md
- INSTALL.md
- README.md
- VERSION
- docs/knowledge-and-commitment.md
- instructions/gtd-weekly-review/SKILL.md
- instructions/ingest-large-tree.md
- instructions/wiki-ingest/SKILL.md
- tools/CONTRACT.md
- tools/chemenu/commands/review_cmd.py
- tools/chemenu/commands/task_cmd.py
- tools/chemenu/review.py
- tools/chemenu/tasks/protocol.py
- tools/chemenu/tasks/superproductivity.py
- tools/chemenu/tests/test_review.py
- tools/chemenu/tests/test_superproductivity.py
- tools/chemenu/tests/test_task_cmd.py

instructions/ingest-large-tree.md

@@ -153,6 +153,13 @@ session.
       already under `raw/` (§ [When to run](#when-to-run) named the volume/breadth trigger that
       put it there). Fill `## Not Extracted` from b.
 
+      This includes step 4's commitment question, asked once **per unit** rather than once for
+      the whole tree: a unit is a subject the same way a single-file `wiki-ingest` source is one,
+      and whether *this* subject opens or closes a loop is only visible while its own extract is
+      in front of you - not at the end of the run, once several subjects' worth of content has
+      gone by. A unit that carries no commitment simply skips the question, the same as any other
+      source (`wiki-ingest` step 4's own "No commitment either way in this source?").
+
    e. **Publish** this unit alone, then tick its checklist line. One unit, one commit.
 
    Do not start unit *N+1* before *N* is published: later units must be able to see the pages