server/brewpi.py: pass physics DT to ServerLogTask (not wall-clock DT_TASK)
so logs carry the correct integration timestep; log startup plant params as
the first PlantParams event so replay_sim can reconstruct them even when no
Sud is ever loaded (previously fell back to hardcoded defaults, causing ~3°C
temperature offset in replay).
tasks/server_log.py: accept and embed dt in log JSON; switch
log_plant_params() to wall-clock monotonic time (same base as sample t),
since the elapsed argument was simulated time and not comparable.
utils/replay_sim.py: switch to open-loop replay (plant driven by logged
power_eff, not sim controller output); use PidFactory so Smith vs Normal
controller type is honoured; set Td=0 in replay plant for Smith mode (logged
temp_ist is already Smith-corrected); feed Smith predictor's internal model
with real power; apply embedded PlantParams mid-run; prefer embedded dt over
sample-based fallback; clamp sim power ≥ 0; replace meaningless sim-power
trace in power subplot with power_set vs power_eff from the log.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>