docs(6209): forty test files — design cascade and stylesheet, embeddings, family canon, forge, backup round trips, inception, placement, platforms, moments, rule move and verification, search scope, facets

Module and test docstrings state what is pinned without the record number
or step that introduced it. Incident accounts become the failure shape in
the present tense: the pipefail head, the code_shapes import, the export
order, the facet dialects, the cross-kind repeat, the write-once kind.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_knowledge_facets.py

@@ -3,14 +3,14 @@
 The facet predicate is written twice by necessity — as SQL for rows the
 database hands back, and as Python for candidates the vector search has
 already fetched — plus a third time as the `is_task` pre-filter that narrows
-the candidate set before it exists. Those three used to be hand-written and
-agreed only by luck: adding `issue` to the SQL arm alone would have set the
-pre-filter to is_task=False, handed the Python arm a candidate set with no
-tasks in it, and returned an empty semantic half for the Issues facet forever
-with nothing red anywhere (#3128).
+the candidate set before it exists. Hand-written, those three
+agree only by luck: adding `issue` to the SQL arm alone would set the
+pre-filter to is_task=False, hand the Python arm a candidate set with no
+tasks in it, and return an empty semantic half for the Issues facet forever
+with nothing red anywhere.
 
-They are now generated from one table. These tests pin the property that made
-the trap possible, so it cannot come back by a different route.
+So they are generated from one table, and these tests pin the property that
+makes the trap possible, so it cannot come back by a different route.
 """
 import pytest
 
@@ -104,8 +104,7 @@ def test_the_live_task_kinds_are_all_facets():
 
 def test_non_task_facets_are_the_note_types_and_only_those():
     """Spelled out rather than derived, so adding a kind to `_FACETS` has to
-    be a deliberate edit in two places. `lesson` joined in milestone 385 step
-    2 (#3729) and is non-task on purpose: `is_task` IS `status is not None`,
+    be a deliberate edit in two places. `lesson` is non-task on purpose: `is_task` IS `status is not None`,
     so a lesson that acquired a status would stop being a lesson."""
     assert set(NON_TASK_FACETS) == {"note", "process", "snippet", "lesson"}