fix(tests): two expectations that the new contract corrected (#4101)

Both were mine, and both show the change behaving as designed.

`test_session_dedup_marks_the_reuse_arms_rather_than_silencing_them` asserted
#12 stays out of the search's `exclude_ids`. It does not, and should not: the
place arm has just listed it, so the semantic arm must not list it again. That
is the same-call rule, not the ledger. The claim I meant — the LEDGER never
reaches the query — is asserted on its own against a record the call has not
otherwise rendered.

`test_a_pulled_snippet_already_seen_is_evidence_not_menu` expected #7 and #8.
It gets #7 alone, because #7 (0.91) now anchors the margin band at 0.81 and #8
scores 0.80. Withholding #7 used to promote a materially weaker hit into a slot
it had not earned, with nothing in the output saying so — the band measures
distance from the best answer, and letting the ledger decide which answer that
is was the axis confusion the rule band was written to avoid.

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

tests/test_write_path_trigger.py

@@ -345,7 +345,12 @@ async def test_session_dedup_marks_the_reuse_arms_rather_than_silencing_them():
     assert "seen" in next(
         line for line in out["context"].splitlines() if "#12" in line
     )
-    assert 12 not in (search.await_args.kwargs.get("exclude_ids") or set())
+    # #12 IS in this call's `exclude_ids`, and that is the other rule working:
+    # the place arm has just listed it, so the semantic arm must not list it
+    # again. What must never reach the query is the LEDGER, which is asserted
+    # on its own in tests/test_ledger_references_not_silence.py against a
+    # record this call has not otherwise rendered.
+    assert 12 in search.await_args.kwargs["exclude_ids"]
 
 
 # --- attribution + telemetry -------------------------------------------------
@@ -1313,9 +1318,14 @@ async def test_a_pulled_snippet_already_seen_is_evidence_not_menu():
     assert 7 not in kw["exclude_ids"]
     assert kw["limit"] == 3
     # ...and the menu carries it, marked.
-    assert out["note_ids"] == [7, 8]
     seven = next(line for line in out["context"].splitlines() if "#7" in line)
     assert "seen" in seven
+    # #8 (0.80) now falls OUTSIDE the margin band, because #7 (0.91) anchors it
+    # at 0.81 instead of being filtered out first. That is the point rather than
+    # a casualty: the band measures distance from the best answer, and the best
+    # answer here is #7 — suppressing it used to promote a materially weaker hit
+    # into a slot it had not earned, with nothing in the output saying so.
+    assert out["note_ids"] == [7]
     # The stamp saw the pull and the resemblance score for this payload.
     skw = stamp.call_args.kwargs
     assert skw["pulled"] == {7: skw["pulled"][7]}