on_step_changed() only re-applies plant params (pot mass/material, L, Td,
grain/water mass) once Sud.step actually changes to a real step - which
doesn't happen on Load (Sud.load() resets step to None), so the controller
kept using whatever the previously loaded Sud (or the generic startup
baseline) had until Start. SudTask.recv()'s Load handler now calls
apply_plant_params() against the new schedule's first step right away, so
the controller already matches the expected plant the moment a Sud is
loaded.
Also replaces server/brewpi.py's hardcoded DEFAULT_PLANT_PARAMS with a
baseline derived from Sud's own (still-unloaded) generic defaults
(EMPTY_SUD's pot_mass/L/Td), used only for the brief startup window before
any real Sud is ever loaded - numerically identical to the old constant.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DkkuG48uHFCGKe6dPSERFk