SAFETY-126: a landing error on the aim is not an overrun

During the night grid charge under the peak reserve the guard alarmed
(ERROR PEAK_GUARD_FLOOR_LIMITED, "Battery stopped limiting the peak") and the
Batteries "Why" said "The peak limit needs power" at quarter ends, while every
quarter landed on the aim. The charge lands the period 0-7 W over the aim and
excess_w()'s 900 / remaining turns that into tens of kW in the last second;
with nothing able to give, check_peak_floor_limited() alarmed on any
wanted > 0.

Each cycle the guard wants power, _peak_landing() asks misses_aim(): with the
batteries at 0 W, does the period end more than ALARM_MISS_W over the aim? If
not, the decision is within_aim: no reserve alarm, no red peak row, no "Why"
peak. The claim and the commands are unchanged. A real overrun under the
reserve alarms on the same cycle as before.

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

goodwe_controller/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## 0.19.2
 
+### 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]]).
+
 **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).
 **Existing installs need no option change:** options that start 0.19.1 also