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_design_stylesheet.py

@@ -120,8 +120,8 @@ def test_the_header_says_what_the_sheet_is_for():
 # --- modes ------------------------------------------------------------------
 
 def test_base_goes_on_the_root_selector_and_other_modes_layer_over_it():
-    """Matches the convention already in the codebase, and the one-way scoping
-    #251 recorded: light on `:root`, dark layered on an attribute selector."""
+    """Matches the convention already in the codebase, and its one-way
+    scoping: light on `:root`, dark layered on an attribute selector."""
     css = render_stylesheet([
         design_token_stub(name="--fs-bg", value_by_mode={"base": "#f5f1e8", "dark": "#14171a"}),
     ])
@@ -188,7 +188,7 @@ def test_a_declared_token_with_no_value_appears_as_a_comment_not_a_silence():
 
 
 def test_an_empty_system_renders_a_sheet_with_no_blocks_rather_than_failing():
-    """A system with no tokens is an ordinary state (rule #115), including one
+    """A system with no tokens is an ordinary state, including one
     that was just created."""
     css = render_stylesheet([])
     assert "{" not in css