Write one field per controlled quantity from PSS/E control blocks

[annacasavant]

Follows the SiennaSchemas #68 and PowerSystems #1820 change of the same name. The OpenAPI writers stop reusing one field whose unit depends on a mode and write the field the mode selects, leaving the rest absent.

• Transformers: the objective picks one actuator band (tap_ratio_limits or phase_angle_limits) and one target band (controlled_voltage_limits, controlled_reactive_power_flow_limits or controlled_active_power_flow_limits) from a pairing table; no COD means all five absent. pti.jl records whether the RMI/RMA and VMI/VMA columns were present before defaults are filled, and psse.jl carries the flags as RM_PRESENT/VM_PRESENT, so the 0.9-1.1 substitute is written only where it is a real tap or voltage default and never as an MVAr or angle band. Phase-angle bands and impedance-correction angle curves convert from degrees to radians.
• LCC lines: MDC maps to control_mode BLOCKED/POWER/CURRENT with one of power_transfer_setpoint or current_transfer_setpoint.
• VSC lines: dc_power_setpoint or dc_voltage_setpoint and power_factor_setpoint or ac_voltage_setpoint per terminal.
• Switched shunts: voltage_limits for the voltage modes, reactive_power_range_limits as a fraction of the regulated device's range for the reactive modes; MODSW 6 maps to DISCRETE_REACTIVE_FACTS.
• Impedance correction: tap_ratio_correction_curve or phase_angle_correction_curve by transformer_control_mode.

device_base.jl drops the :dynamic classification, since no field's unit depends on a mode any more. A synthetic v35 fixture covers every presence combination.