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_integration_snippet_locations.py

@@ -1,4 +1,4 @@
-"""Real-Postgres integration test for the snippet location reverse lookup (#2083).
+"""Real-Postgres integration test for the snippet location reverse lookup.
 
 Runs only in the CI integration lane (real Postgres, schema built by
 `alembic upgrade head`, which includes migration 0070's `notes.data` + GIN index).