The call record: every model call, for the operator's study (M6.6a)

nisse-core records each model call of every agent into a file beside its
state store (<state>.calls.db), for the status page (L7, X6):

- the request body exactly as sent (never headers), the raw response with
  its reasoning, the model asked and the one that answered, time, tokens
  and llama-server's own prompt reuse (timings.cache_n);
- its work item, role, run and purpose: Driver.run and nisse-dev's
  delegation loop open runs, nested; compaction, expert consults, the
  classifier and the go-ahead reader label their calls;
- provenance, worked out in BudgetedClient by comparing the events at
  each stage: each event sent with its log id and content as sent, which
  a compaction replaced, which fitting shortened (by how much) and
  dropped.

Content is stored once by hash, compressed. It is diagnostic only: the
agent never reads it, a failed write is logged once and recording stops
while the call goes on, and the file is deleted when the agent starts,
so its layout never migrates; CallReader refuses a layout it doesn't
know. While recording, the system prompt ends with one sentence saying
so. `call_record: false` in either agent's YAML turns it off.

The benchmark records each run beside that run's own state store, and
`--keep-runs DIR` keeps both for the page.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01J5Utyfzw7gF7UhjRDEtjTk

nisse-dev/tests/test_config.py

@@ -573,3 +573,28 @@ def test_the_vault_is_read() -> None:
 def test_a_bad_vault_is_refused(vault: dict[str, Any], said: str) -> None:
     with pytest.raises(ConfigError, match=re.escape(said)):
         build(vault=vault)
+
+
+def test_the_call_record_is_on_unless_turned_off() -> None:
+    assert build().call_record is True
+    assert build(call_record=False).call_record is False
+    with pytest.raises(ConfigError, match="call_record"):
+        build(call_record="no")
+
+
+def test_both_routes_record_into_one_file_beside_the_state_store(
+    tmp_path: Path,
+) -> None:
+    from nisse_core.models.catalog import ModelCatalog
+    from nisse_dev.loop.build import make_llm_clients
+
+    normalized, passthrough = make_llm_clients(
+        build(state_db=str(tmp_path / "state.db")), ModelCatalog({})
+    )
+    assert normalized.call_recorder is passthrough.call_recorder
+    assert normalized.call_recorder.path == tmp_path / "state.calls.db"
+    off, _ = make_llm_clients(
+        build(state_db=str(tmp_path / "other.db"), call_record=False), ModelCatalog({})
+    )
+    assert off.call_recorder is None
+    assert not (tmp_path / "other.calls.db").exists()