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_family.py

@@ -1,4 +1,4 @@
-"""The promotion engine without a database (milestone 463 step 3).
+"""The promotion engine without a database.
 
 The parts that decide — which citations claim lineage, which criteria veto —
 are pure and pinned here, beside the doors' wiring: the triggers ride the
@@ -89,7 +89,7 @@ def test_proven_needs_named_evidence():
 
 
 def test_the_criteria_the_agent_is_told_are_the_ones_enforced():
-    """Rule 119: the criteria are product text. The promote tool's docstring
+    """The criteria are product text. The promote tool's docstring
     must name every criterion the service checks, by its parameter name."""
     doc = family_tools.promote_family_idea.__doc__
     for key in CRITERIA_KEYS: