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/freshness.py

@@ -87,6 +87,10 @@ when it has not moved THROUGH A CHANGE IT WAS OBLIGED TO FOLLOW:
                 AND |standing command now - standing command when the reading
                      last changed| >= MOVE_W
 
+SAFETY-94: "unchanged for" counts only the reads at which both command terms
+held, so a register that rested is not judged before it could answer.
+DECISIONS/SAFETY-94-lagging-battery.md.
+
 0x0518 is the inverter reporting ITSELF and it tracks its own command: r = 0.998
 with battery power against r = 0.09 with the real meter (goodwe/NOTES.md §3.3),
 command and actual agreeing within 4 W once settled (§5.10, 2026-08-22), and the
@@ -216,6 +220,8 @@ change - which was the ONLY exit - has a median of 143 s, 17 episodes at or
 over the live one's 710 s, and a worst case of 21440 s. That distribution is a
 property of this battery's firmware. It is not a property of this code, and the
 add-on must not depend on it.
+SAFETY-94: many were the gate judging a rested register on its first read
+(SAFETY-58). Counted from the ask, the same days give 59 trips.
 
 THE RULE, and it is SAFETY-13's shape one module over - "which latches get an
 exit, not how long the block lasts":
@@ -372,7 +378,9 @@ BOUNDS = {
                    "SAFETY-57: the verdict is withdrawn after 17.0 s of the "
                    "standing command below 250 W, because at 0 W the register "
                    "is obliged to nothing and the verdict cannot be tested "
-                   "again from inside the state it creates"),
+                   "again from inside the state it creates. SAFETY-94: the "
+                   "35 s counts only reads at which the command asks the "
+                   "register to move"),
     "soc": Bound(
         signal="soc (0x050E, pack SoC, U16, 1 %, 10 s publish)",
         unchanged_s=float("inf"),
@@ -416,11 +424,9 @@ class Freshness:
     new grading window at that instant. The 1 Hz oscillation the latch exists to
     prevent is still prevented: the new window is `bound.unchanged_s` wide, so
     no re-trip can land sooner than 35 s after a release, rather than on the
-    next read. ⚠️ MEASURED FROM THE RELEASE, NOT FROM THE COMMAND RESUMING - if
-    the site rests for longer than the window before it asks for anything, the
-    window is already old and the re-trip lands on the first read at which the
-    command travels 250 W again. That is survivor 5's shape, it predates this
-    card, and its cost is one `stale_input_s` hold.
+    next read. SAFETY-94: the 35 s counts only while the command asks the
+    register to move, so a site that rests after a release is not re-tripped
+    on its first ask.
 
     ⚠️ TWO CLOCKS, AND THE DISTINCTION IS THE WHOLE OF SAFETY-57'S HONESTY.
     `changed_mono` / `held` are facts about the REGISTER: when it last carried a
@@ -451,6 +457,11 @@ class Freshness:
         # the change-stamps; `_release()` is where they diverge.
         self.graded_from = None
         self.standing_at_grade = None
+        # SAFETY-94. Seconds of this window during which the register was
+        # obliged to move (the command at least `move_w` and `move_w` away
+        # from `standing_at_grade`), and the instant of the last read.
+        self.obliged_acc = 0.0
+        self.last_read = None
         # The instant the standing command last FELL below `move_w`, or None
         # while an obligation is standing. The release timer runs off this.
         self.rested_since = None
@@ -499,6 +510,7 @@ class Freshness:
         # it reads in the order the state machine moves - withdraw, then
         # re-grade - not because the code depends on it.
         self._release(standing_w, now_mono)
+        self._oblige(standing_w, now_mono)
         self._grade(standing_w, now_mono)
 
     def _open_window(self, standing_w, now_mono) -> None:
@@ -510,6 +522,35 @@ class Freshness:
         self.graded_from = float(now_mono)
         self.standing_at_grade = (None if standing_w is None
                                   else float(standing_w))
+        # The read that opens a window is never an ask (no travel yet).
+        self.obliged_acc = 0.0
+
+    def _obliged(self, standing_w) -> bool:
+        """Is the register asked to move: the command is at least `move_w` and
+        has travelled `move_w` since the window opened?"""
+        if standing_w is None or self.standing_at_grade is None:
+            return False
+        standing_w = float(standing_w)
+        return (abs(standing_w) >= self.bound.move_w
+                and abs(standing_w - self.standing_at_grade)
+                >= self.bound.move_w)
+
+    def _oblige(self, standing_w, now_mono) -> None:
+        """SAFETY-94. Count only the time the register was asked to move.
+
+        A register that held still while nothing asked it to move has not
+        failed, so time before the command moved is not evidence. The time
+        since the previous read counts when the obligation stands at this
+        read; a command flapping in and out of the obligation still adds up.
+        """
+        now_mono = float(now_mono)
+        if self.last_read is not None and self._obliged(standing_w):
+            self.obliged_acc += max(0.0, now_mono - self.last_read)
+        self.last_read = now_mono
+
+    def obliged_s(self) -> float:
+        """Seconds of the current window the register was obliged to move."""
+        return self.obliged_acc
 
     def _release(self, standing_w, now_mono) -> None:
         """SAFETY-57. Withdraw a verdict whose obligation is no longer standing.
@@ -543,7 +584,12 @@ class Freshness:
         if self.stale or self.graded_from is None:
             return
         held_s = self.graded_s(now_mono)
-        if held_s < self.bound.unchanged_s:
+        # SAFETY-94 (closes SAFETY-58): the bound counts only the time the
+        # command asked the register to move, not the time since it last
+        # changed. A register that rested for minutes was otherwise judged on
+        # the first read after a new command, before it could answer (live,
+        # 2026-10-03: 1 s after the command).
+        if self.obliged_s() < self.bound.unchanged_s:
             return
         # ⚠️ BOTH None GUARDS ARE FOR A CALLER THAT DOES NOT KNOW ITS OWN
         # OBLIGATION YET, WHICH IS NOT `_read_unit`. `Inverter.standing_w()`