SAFETY-94: a healthy battery that lags or reverses is not flagged as frozen or refusing

The stale-reading gate counted its 35 s from the register's last change, so
after a rest the first read after a new command tripped it (SAFETY-58; live
2026-10-03, four trips 1 s after the command). It now counts only the time
the command asked the register to move.

At N=1 the refusal engaged after 12 frozen cycles if the reading was under
100 W at that moment, which a battery reversing through its lag passes at a
1 s meter. The refusal now needs the N>1 evidence at every roster size: under
100 W, one way, for 12 cycles spanning 22 s, restarting when the reading
moves 50 W towards the ask.

DECISIONS/SAFETY-94-lagging-battery.md; test_safety94.py.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

goodwe_controller/app/inverter.py

@@ -321,13 +321,14 @@ class Inverter:
         # take, 0 none), when that refusal or its last probe started, the
         # current probe's start, and the cycles of evidence so far and when
         # they began. Memory only, like SAFETY-52's: stop and start end it.
-        # Used at N>1 only.
+        # The evidence count is also used at N=1 (SAFETY-94); the rest at N>1.
         self.refused = 0
         self.refused_at = None
         self.probe_from = None
         self.ref_count = 0
         self.ref_since = None
         self.ref_sign = 0
+        self.ref_from = None
 
     # -- store ---------------------------------------------------------------
     def key(self, name: str) -> str: