- Add concurrent_slots config (fused_engine section, default 1)
- Create executor_shared_t with shared in_flight table + queue mutex for multi-thread
- Move in_flight state from executor_thread_t to executor_shared_t (cross-thread isolation)
- event_executor_thread: per-thread entry point, N threads created in main.c
- Add fundsIncrement to trading_pair_t, triangle_t, signal_leg_t (fetch from KuCoin API)
- Use funds_increment for rounding market buy quote_cost (evaluate.c) and increment floor (executor.c)
- Fix leg 0: remove double-counted apply_fee_hold (evaluate already accounts via ff)
Engine (evaluate.c):
- Compute per-leg minimum order size from quoteMinSize
(max(baseMinSize * price, quoteMinSize), rounded to quoteIncrement)
- Convert each leg's minimum to starting-quote via pure-rate product (no fees)
- Viability gate: skip triangle if candidate < min_volume (strictest leg)
- Floor starting_volume at min_volume; supersedes old base_min_size guard
Data (symbols_api.h, triangle.h, symbols_api.c):
- Parse quoteMinSize from KuCoin /api/v2/symbols; propagate to triangle struct
Executor (executor.py):
- Remove _precheck_volume: sizing is the engine's responsibility
- Live mode: don't deduct estimated fee from filled_volume (exchange nets fees)
- Live mode: LegFill.fee always zero
Two-process architecture: a C17 fused engine (WebSocket order book
mirror, triangle enumeration, real-time profitability evaluation)
communicating via Unix domain socket to a Python 3 executor (order
placement with paper/live trading modes, REST control API).
Targets KuCoin spot market.
nicolas