Reworks the P1 sim so the four §7.1 exit criteria are demonstrated against the
ACTUAL mechanic, not a model (resolves the verifier's "sim models the ledger,
not the LangGraph integration" finding).
- New tests/sim/test_p1_graph_integration.py drives the real agent_team.graph
StateGraph (interrupt/Command(resume)) + the real langgraph SqliteSaver
checkpointer + the committed pending_questions compare-and-set, proving:
(a) suspend survives a simulated restart (drop saver/conn, rebuild over the
same checkpoint DB) and resumes; (b) duplicate answer loses the CAS and the
graph never double-advances; (c) a post-deadline answer loses to expire and
the task is not resumed; (d) two concurrent tasks resume to the correct
thread, with a turn-guarded no-double-apply check.
- graph.py: derive a STABLE question_id from uuid5(thread_id, turn). The
clarifier node replays on resume, so the prior fresh-uuid id changed between
the delivered/ledgered question and the qa_history entry — breaking the
§3.3.1 identity contract. Now the delivered id == ledger key == history entry
(unit-tested in test_graph.py).
- harness._connect() now uses the committed schema.connect() (WAL + busy_timeout)
instead of a raw sqlite3.connect, so concurrent responders genuinely serialize;
the criterion-(d) concurrency test no longer swallows OperationalError (it
asserts zero errors + exactly one CAS winner).
- requirements.txt: pin langgraph-checkpoint-sqlite==3.1.0 (design D9 durable
checkpointer), now exercised by the integration test.
Full suite: 564 passed; ruff + format clean.
