fix(tests): the trigger backfill assumed keyword calls; three fixtures pass positionally (#4099)

CI run 6937 red — 3 collection errors, `positional argument follows keyword
argument`, in the three integration fixtures that call the service positionally
(`create_rule(topic.id, uid, "title", "statement")`). The script that added
`when_to_apply=` to 15 fixtures inserted it as the FIRST argument, which is
valid only where every other argument is already a keyword.

Moved to the last argument in every call, which is legal in both styles, and
the continuation indent now matches the surrounding arguments.

Also repairs self-inflicted damage: the same script added a trigger to the two
tests in test_rule_trigger_required.py whose whole purpose is to call the
creators WITHOUT one. They would have stopped raising and the guard's own
proof would have inverted — a test that passes for the opposite reason than
the one it names, which is worse than a failing one.

Caught by ast.parse across tests/ rather than by the next CI round trip.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01821k5B3Ysecp9fNYs92Kuy

tests/test_preference_write_path.py

@@ -9,8 +9,7 @@ a rule binds should have agreed to be bound.
 A preference inverts it. The operator's framing: *"preferences are rules that
 scribe can and should update during use."* A preference that asks every time
 never drifts, and drifting is the whole feature. Reaching one through
-`create_rule(kind=...)` would mean reading it through the gate's prose, and
-when_to_apply="when the moment this fixture stands in for arises",
+`create_rule(kind=..., when_to_apply="when the moment this fixture stands in for arises")` would mean reading it through the gate's prose, and
 the caller would hesitate over exactly the act this kind exists to make
 routine.