SAFETY-136: a gentler loop on a slow meter until the last move shows

On a meter whose readings come 4 s or more apart, the loop runs at half its
gain after a move of 150 W or more, until the meter has fallen by half of the
move or 2 cycles have passed. With readings 10 s late on a 5 s meter the export
falls 44 % over oven, kettle and hob, owner shape, steps; 1-2 s meters are
untouched.

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

goodwe_controller/app/main.py

@@ -63,6 +63,7 @@ from .clamp import (
 )
 from . import freshness
 from . import lateness
+from .settle import Settle
 from . import dayview, homeview
 from .daycurve import SolarToday
 from . import handback
@@ -741,6 +742,7 @@ class Controller(InputsMixin, WritesMixin, TradeMixin, CycleMixin, AlarmsMixin,
         self._arb_action = None
         self.inputs_bad_since = None
         self.answer = lateness.Answer()           # SAFETY-128
+        self.settle = Settle()                    # SAFETY-136
         self._late_logged = self._late_zero = False
         # SAFETY-03: what the loop's OWN bounds did last cycle, `(engaged,
         # note, over_rating)` (SAFETY-40 splits the last out). Site-level: the