HostSim FOC support: run loaded graph in simulator and add FOC runtime layout

[datacrystals]

Summary

This PR fixes two blockers that prevented the FOC demo graph from actually running in HostSim:

1. Build Simulation always built the SPWM demo graph, regardless of which graph was loaded in NodeGUI.
2. The runtime plot layout was hardcoded to the SPWM demo (gate signals / duty / phase currents), so even if FOC telemetry arrived it was plotted in the wrong context.

Changes

• HostSim platform API stubs (Images/HostSim/include/platform_api.h, Images/HostSim/src/platform_api.cpp):

  • Added the missing functions the FOC demo graph calls:
    • platform_get_motor_rpm
    • platform_phase_voltage_u/v/w
    • platform_get_throttle_valid
    • platform_digital_read/write
    • platform_can_send/rx

• HostSim launcher scripts (Images/HostSim/scripts/run_spwm_live.sh, .ps1):

  • Added --graph / -Graph and --scenario / -Scenario arguments.
  • Scenario defaults to a file matching the graph name (with _graph suffix stripped), falling back to default_motor.json.
  • Backward compatible: calling without --graph still runs the SPWM demo.

• NodeGUI Build Simulation (Source/NodeGUI/src/MainWindow.cpp):

  • Passes the currently loaded graph to the launcher instead of hardcoding SPWM.

• Runtime plot layouts (Source/NodeGUI/src/runtime/RuntimeTab.cpp/.h):

  • Added a FOC preset: cg_id_a/cg_iq_a, cg_vd_v/cg_vq_v, cg_iu_a/cg_iv_a/cg_iw_a.
  • Added a FOC button next to the existing SPWM preset button.
  • Auto-detects FOC graphs when cg_id_a telemetry is present and applies the FOC layout; falls back to SPWM layout on duty_u.

Verification

• cmake --build build --target NodeGUI succeeds.
• Linux launcher tested with both SPWM and FOC graphs:
  • bash Images/HostSim/scripts/run_spwm_live.sh --no-gui --force-emit
  • bash ... --graph Assets/Examples/foc_demo.json --no-gui --force-emit

Known limitations / follow-up work

HostSim is still a simplified SIL backend. The items below need to be addressed before this can be considered a true HAL-level SIL simulator:

• Ngspice plant backend: Images/HostSim/src/plant/ngspice_plant.cpp exists but is not wired as the default. FOC graphs should run against an ngspice inverter/motor netlist, not the built-in ODE motor model.
• Non-realtime ngspice execution: ngspice will not run at realtime 10 kHz ISR rates. Need a time-scaling / co-simulation scheduler that decouples simulation wall-clock from firmware ISR time.
• Command injection / CAN simulation: platform_can_rx is currently a no-op. The simulator needs a way to inject control-start commands, throttle commands, and config writes so the firmware does not sit waiting for a control-start frame.
• Preset firmware state: Provide scenario-level hooks to pre-arm the control state, skip boot waits, and pre-load config values (e.g. Ctrl.ThrottleEnable, current limits) so valuable simulation time is not spent simulating idle startup.
• Sensor noise and non-ideality: Add configurable noise, offset, gain error, and quantization to phase currents, DC-link voltage, encoder angle, and throttle inputs.
• HAL-level platform API: Several stubs are currently fake (digital IO no-ops, phase voltages computed as duty * vdc / 100, CAN no-ops). These need to be backed by the simulated plant/netlist.
• Graph-specific scenario selection: The scenario heuristic is crude; NodeGUI should allow picking a scenario per graph or embed scenario metadata in the graph JSON.

/cc @hibyemy