run_simulation takes 15 positional parameters and 9 config dataclasses from one file, with no runtime schema — every caller is welded to the core's shape

[dim-sous]

What is wrong

core/simulator/core.py:54-69:

def run_simulation(strategy, forecast_e, forecast_r, probabilities,
                   realized_e_prices, realized_r_prices,
                   bp, tp, ep, mp, ekf_p, thp, elp, reg_p, pp=None) -> dict:

Fifteen positional parameters; nine of them config dataclasses (BatteryParams, TimeParams, EMSParams, MPCParams, EKFParams, ThermalParams, ElectricalParams, RegulationParams, PackParams), all defined in one 373-line file core/config/parameters.py. Seven call sites (comparison/*.py ×3, tests/*.py ×2, plus internal) each build all nine and pass them in order.

Consequences:

• The signature is the welding medium. Every seam issue (The estimator has no seam: EKF hardcoded in the loop, EKFParams welded into run_simulation, its name baked into the traces — a UKF touches 6–10 files #2, The plant is a type switch: BatteryPack if use_pack else BatteryPlant — a third plant model is another branch in the core #3, Activation generator and ledger are hardcoded in the loop; ledger.py and milp_bidding.py import upward from core.simulator #4) hits this: adding or replacing a component means adding or replacing a positional parameter, at seven sites.
• No runtime schema. There is no way to ask "what are the settable fields of this experiment?" without reading source. RCWS answers that off the dataclasses in ~40 lines (simulation/config.py: dotted --set path=value, typed coercion, typo'd keys refused, config_fields() for any view). Nothing here can offer a --set, a form, or a record of what was set.
• Strategy(str, Enum) at parameters.py:283 collides by name with the real Strategy dataclass in core/simulator/strategy.py — a leftover that a reader has to disambiguate.

What it should be

• One experiment config object composed of the parameter dataclasses (nesting is fine — that is what dotted paths are for), passed as one argument.
• The introspection RCWS already has: fields, types, defaults, and later knob metadata (label, unit, doc, bounds, choices) — the declaration a form and a --set both read.
• Component configs travel with their component (an estimator carries its EKFParams), so run_simulation never names one.

Done when

• run_simulation(strategy, experiment_config) — or equivalent — and every caller migrated.
• config_fields() returns every settable path; a --set path=value override engine exists and refuses unknown keys.
• The stray Strategy enum is gone or renamed.
• Proof: bit-identical traces at every caller.

Phase 1 of the platform epic; the piece the records (phase 2) are recorded from. Depends on #1.