docs(6209): the remaining test files — lessons, reply moment and shape, retrieval specs and scopes, rule doors and judgments, services, snippets, search scope; five tests renamed to their property

Docstrings, section headers and assertion messages drop the record number,
milestone or step that introduced the behaviour, and incident accounts are
restated as the present-tense failure shape. A dead pointer to a design doc
that is not in the repo is removed.

Renamed to the property they check:
  test_the_old_shape_would_be_caught -> test_a_rank_then_scope_query_is_caught
  test_a_ledger_repeat_no_longer_produces_that_case_at_all -> test_a_ledger_repeat_is_counted_not_withheld
  test_the_header_no_longer_promises_once_per_session -> test_the_header_explains_the_seen_marker
  test_the_portal_case_no_longer_stamps_one_canon_onto_a_whole_file -> test_one_canon_is_not_stamped_onto_a_whole_file
  test_the_repos_own_prose_no_longer_defines_with -> test_the_repos_own_prose_does_not_define_with
  test_the_original_regression_create_note_with_content -> test_the_real_server_refuses_content_on_create_note

Fixture and example ids stay: "note 5" in a supersession chain, "rule 156"
in an illustrative question, `#2275` as the hex-versus-citation case,
`#3244` as the example of a bare number, fixed dates in date-filter tests.

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

tests/test_lesson_convergence.py

@@ -1,4 +1,4 @@
-"""Convergence named at the write (milestone 440, #4634).
+"""Convergence named at the write.
 
 When a lesson is answered "no rule fits", the response looks for other
 no-rule lessons in the same situation and, once there are enough, names the
@@ -53,7 +53,7 @@ def test_one_incident_written_up_three_times_is_not_a_recurring_situation():
     assert links_svc.convergence_group(same) is None
 
 
-# ── The bar is relative to each lesson's own register (#5193) ──────────────
+# ── The bar is relative to each lesson's own register ──────────────────────
 
 
 def test_too_little_background_says_nothing_stands_out():
@@ -138,7 +138,7 @@ async def test_lessons_that_stand_out_together_are_named():
 
 @pytest.mark.asyncio
 async def test_a_large_no_rule_pool_in_one_flat_band_names_nothing():
-    """The #5193 failure: every lesson answered "no rule", every score above
+    """The flat-band failure: every lesson answered "no rule", every score above
     a fixed bar, and a group the size of the pool. Nothing stands out of a
     flat band, so nothing is named however large the pool grows."""
     a, b, c = _run(no_rule=set(_NOTES), sim=lambda x, y: 0.66 + 0.01 * ((x + y) % 5))