SAFETY-126 round 2: state what the 10 W tolerance costs; test the latch reset

Text only (DECISIONS, DOCS, CHANGELOG): a step load alarms on the same cycle
as before; a steadily rising load alarms a little later; with peak_margin_w 0
a period can end up to 10 W over the limit without this alarm, as for 'Load
too high' (SAFETY-81). Owner accepted 2026-10-31.

test_safety126.py part 2: after a real overrun ends, _peak_landing()'s latch
is reset and the night's later landings are quiet (review F3).

Co-Authored-By: Claude <noreply@anthropic.com>

goodwe_controller/CHANGELOG.md

@@ -4,7 +4,7 @@
 
 ### Not in a release yet
 
-- The night grid charge no longer raises "Battery stopped limiting the peak" when the 15-minute period stays on the aim ([[SAFETY-126]]).
+- The night grid charge no longer raises "Battery stopped limiting the peak" when the 15-minute period stays on the aim. A steadily rising load now alarms a little later, and with a peak margin of 0 a period can end up to 10 W over the limit without this alarm ([[SAFETY-126]]).
 
 **A patch bump: one fix for charging from the grid under the peak limit, and no option changes.**
 No option was added, removed or renamed, and no default changed (86 options).