docs(6209): preference door, systems and notes tools, lesson surfacing, rule versions, backup round trip, JSON reader, charter search, provenance, location filter

Ten more test files: issue, milestone, rule, decision and snippet numbers
come out of docstrings, comments and messages; the preference door states
what a preference is instead of quoting the framing; the JSON reader says
why jq is not assumed instead of what every hook used to do; the backup
round trip's column warning no longer claims the import side is unguarded.

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

tests/test_lesson_surfacing.py

@@ -1,11 +1,11 @@
-"""A lesson reaches the session it applies to — milestone 385, step 5.
+"""A lesson reaches the session it applies to.
 
 Three decisions are guarded here, and each has a way of going quietly wrong
 that these tests are shaped to catch rather than to describe:
 
   WHICH ARM. The two note arms, and no new one. An arm that FILTERS kinds does
   not merely outrank a kind it omits — it makes it unreachable, and nothing
-  reports an arm that never had the candidate (#3702). The write path filters;
+  reports an arm that never had the candidate. The write path filters;
   the prompt menu does not, but is project-scoped, which for a kind whose whole
   claim is that it transfers amounts to the same silence.
 
@@ -115,8 +115,8 @@ async def test_the_write_path_asks_for_lessons_at_all():
 async def test_a_lesson_takes_a_reserved_slot_and_the_query_is_logged():
     """The slot is a claim that a kind deserves a guaranteed line. A claim like
     that has to be falsifiable from the first deploy, which means its own query
-    in `retrieval_logs` — #2463's finding, recorded about the slot that shipped
-    without one."""
+    in `retrieval_logs`; a slot without one cannot be judged against what it
+    displaced."""
     rec = MagicMock()
     out, calls = await _menu(
         [(0.70, fake_note(id=1, title="Badge layout task", user_id=1, is_task=True))],
@@ -143,7 +143,7 @@ async def test_the_reserved_lesson_extends_and_never_evicts():
     """It sides with `preference_slot` over `reuse_slot`, and the reason is the
     ledger rather than taste: an evicted hit was RETURNED by the general search
     and sits in that call's log row, so displacing it makes the two tables
-    disagree about one call for a reason nothing in the data explains (#3668).
+    disagree about one call for a reason nothing in the data explains.
     The voice argument points the same way — a record that binds nothing should
     not be able to throw a better-scoring one off the menu."""
     main = [(0.72, fake_note(id=1, title="a", user_id=1)),
@@ -190,7 +190,7 @@ async def test_a_weak_lesson_does_not_buy_the_slot():
 
 @pytest.mark.asyncio
 async def test_the_slot_surfacing_matches_its_own_retrieval_row():
-    """#3668's identity, on the new arm: what a source says it retrieved and
+    """The two-table identity, on this arm: what a source says it retrieved and
     what it says it showed must be the same records. The reserved lesson is
     fetched by `lesson_slot`'s query, so it is `lesson_slot`'s surfacing —
     counting it under `auto_inject` as well would book one delivery twice and
@@ -275,7 +275,7 @@ async def test_the_write_path_names_the_register_for_a_lesson_too():
 
 
 def test_the_surfacing_guards_can_fail():
-    """Rule 167: each assertion above has to be able to bite. The three shapes
+    """Each assertion above has to be able to bite. The three shapes
     it would take to break this feature silently, each checked here against the
     condition the tests actually assert on."""
     # An arm that stops asking for the kind.