SAFETY-73 review: a refusal needs 22 s of evidence, and the cut-out warning is for giving only

- REFUSED_SPAN_S: the 12 cycles of evidence must also span (SETTLE_CYCLES-1) *
  LOOP_TICK_S = 22 s. At a 1 s meter, lagged healthy readings refused both
  units 10-16 times an hour after load steps (site held 0 W). 2 s and slower
  ticks are unchanged.
- REFUSES_ABOVE_CUT_OUT only for a refusal to give power: a full battery that
  stops taking charge is always above its cut-out level.
- test_delivery: its wedged fixture (0.2 s cycles) no longer reaches a refusal;
  the release/1.0 checks are restored and a span check added.
- test_refusal_units: lagged-reading and full-battery plants, two new checks,
  U14/U15 in the mutation table. Stale "> 500 W" wording fixed. DOCS/DECISIONS.

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

goodwe_controller/app/inverter.py

@@ -319,12 +319,14 @@ class Inverter:
 
         # SAFETY-73. The direction this unit's battery refuses (+1 give, -1
         # take, 0 none), when that refusal or its last probe started, the
-        # current probe's start, and the cycles of evidence so far. Memory
-        # only, like SAFETY-52's: stop and start end it. Used at N>1 only.
+        # 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.
         self.refused = 0
         self.refused_at = None
         self.probe_from = None
         self.ref_count = 0
+        self.ref_since = None
         self.ref_sign = 0
 
     # -- store ---------------------------------------------------------------