Two related accounting fixes:
1. _calibrate_fee_model startup guard: before calling calibrate_fee,
compute raw deviation from the published taker/maker rate (ignoring
any stale calibration_ratio). If >15%, skip and log WARNING rather
than letting a bad REST fill set calibration_ratio to ~0.8 and cause
ESTIMATED fees to understate actuals by 20% for the entire session.
2. fee_settled_events trade_id: BingX WS does not echo back our
clientOrderId in fill events (field "c" is empty). Was falling back
to BingX's internal orderId (p-e-mq5.../p-x-mq5...) which can't
be joined to trade_events. Now reads trade_id from kernel slot 0
(which retains the trade_id until the next ENTER) so
fee_settled_events.trade_id = BTCUSDT-T-N. Added venue_order_id
field to persist_fee_settled for bidirectional reconciliation.
128/128 tests green.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
9e210b5a02