[Pot] - removed the gain (efficiency) factor and the separate
"theta" initial-temperature param; Pot now starts at theta_amb and
set_power()/get_power() operate on p_in directly. Added
set_ambient_temperature() for live ambient updates. Dropped the
now-unused "theta"/"gain" keys from Model/Plant in config.json.sim
and config.json.templ (also fixes a JSON syntax error in
config.json.templ: trailing commas left over after removing "gain"
made Model/Plant fail to parse).
[Sensor] - fix missing space in TempSensorSim.temperature()'s
offset/variance expression (cosmetic, no behavior change).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>