SAFETY-57: the stale-reading verdict gets an exit, because its own consequence is what stopped it being tested

SAFETY-37's freshness gate reports a battery-power register as MISSING when it
stops following its own command, and a missing input is "command 0 W and keep
commanding" (§11.1 rule 1). The gate's only exit was "an arrival carrying a
DIFFERENT number" - and at 0 W nothing is asking the register to be anywhere.
The state had no exit reachable from inside it, and the log line promised the
opposite in the same sentence that announced the 0 W.

REPRODUCED FROM THE WIRE, NOT MODELLED. scenarios/safety57-2026-09-21/ is 3840
verbatim frames off the RS-485 pair, read from the passive sniffer, decoded by
tools/decode_bus_capture.py (0 unparsed, 0 bad CRC, 0 unknown shapes; the
mode->sign convention is graded off the capture, not trusted). The box was
running 0.10.0, so the 0 W in the trace IS the add-on's own claim:

  10:51:24.7  0x0518 reaches -3 W. Pack at 11 %, the BMS refuses the discharge,
              the inverter idles. THE REGISTER IS HEALTHY AND TRUTHFUL.
  10:51:29.7  the command reaches +1060 W - 800 W of travel
  10:52:00    the conjunction arms. Inverter.batt becomes None
  10:52:21.7  the site commands 0 W, on the wire
  ...         0x0518 does not change value for 850.0 s. The setpoint does not
              change value for 790.0 s. The house exports 2.4 kW throughout
  ~11:04      a human restarts the add-on. That is what ends it

AND IT HAD BEEN ESCAPING BY LUCK. Replaying the committed 16-day loop capture
through the shipped conjunction finds 93 trips whose wait for the BMS
keep-alive pulse that cleared them has a median of 143.4 s, a worst case of
21440.1 s, and 17 of 93 at or beyond this episode's 710 s. That distribution
belongs to the battery's firmware, not to this code.

THE CARD'S OPTION 2 ALREADY HELD AND IS NOT THE BUG. _grade() has required
|standing| >= MOVE_W since SAFETY-37. The trip was at +1060 W and the stuck
state is at 0 W; they are different moments, and an entry-side rule cannot
reach a state entered legitimately and then persisted. Nothing in the
conjunction is weakened here.

THE RULE, SAFETY-13's SHAPE ONE MODULE OVER - which latches get an exit, not
how long the block lasts:

  the verdict is withdrawn when the obligation that produced it has been gone
  for RELEASE_S, and the register is then re-graded from scratch.

RELEASE_S is BATT_OBLIGED_S, 17.0 s - the obligation window already derived in
the file (6.0 plant + 10.0 publish + 1.0 read), taken at the FLOOR of its band
for the mirror of MOVE_W's reason. Which half is safe is the opposite of
SAFETY-13's: being wrong long is the failure being fixed, being wrong short
costs one bounded re-grading window. Below 17 s the release pre-empts the
cheaper exit - the register answering by itself - and that is graded
behaviourally, not asserted.

The whole parked interval is now stale_input_s + RELEASE_S = 32 s. On the live
episode: telemetry back at 10:52:39 instead of 11:05:35, with 0x0518 still
answering the same -3 W. RED BEFORE (release_s=inf, a graded counterfactual and
not a second implementation), GREEN AFTER.

WHAT IT COSTS, AND IT IS NOT SMALL. A register dead for good is re-graded for
ever: over 1201 reads the held number reaches a consumer on 630 (52.5 %)
against 35 (2.9 %) before. Payable only because one window is at most 35 s and
the two consumers hold for 75 s and 85 s, so neither can reach a verdict inside
one and the re-trip clears both windows. No detection SAFETY-37 had is given
back - a permanent None clears the same windows for ever too - and the command
is derived from the P1 meter, never from batt.

Two clocks, deliberately: changed_mono/unchanged_s() stay facts about the
REGISTER, graded_from/graded_s() are the VERDICT's window. Collapsing them
either lies to the operator or defeats the re-grading.

main.py's stale line had its ESCAPE CLAUSE corrected - it promised a clearance
the state could not produce - and gained a STALE WITHDRAWN edge that says in
its own words that nothing has been learned about the register. The DIAGNOSIS
half is SAFETY-56's and is deliberately untouched, with a named check asserting
it is still there so that rewrite has to be deliberate.

Battery: 22 mutations, 21 red, 1 argued equivalent, 0 unexplained survivors.
Two findings kept in DECISIONS: _release()'s move_w test swapped for
unchanged_s SURVIVED at +5 B because every fixture rested at exactly 0 W (habit
11, closed by a 0/100/300 W fixture); and the code shipped a habit-22 comment
claiming the _release/_grade order was load-bearing, which the battery
falsified - the two act on mutually exclusive predicates, so the order is not
observable. MUTATION.md gains habit 23 for a mutation that ran, fingerprinted
clean, and was a no-op on the fixture because `0.0 or x` is x.

Suite: 30/30 in the CI image, checks.yml's exact command, purged tree, :ro, one
file at a time.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BwRLw7eKYj2byVdwB6kbjU

goodwe_controller/MUTATION.md

@@ -852,6 +852,50 @@ Cheap habits fall out of it, and all of them are now used in this repository:
     invented justification for a correct decision is still a defect, and it is
     the kind a reviewer cannot see because the code is right.
 
+23. ⚠️ **THE MUTATION IS SUBJECT TO EVERY HABIT ABOVE, HABIT 4 INCLUDED - AND
+    THE PURGE, THE FINGERPRINT AND THE BYTE DELTA ALL SAY IT TOOK.** SAFETY-57's
+    battery reported a **survivor at +21 B** for a mutation of
+    `Freshness._open_window()`: `self.graded_from = float(now_mono)` rewritten
+    as `float(self.changed_mono or now_mono)`, which is meant to re-anchor the
+    verdict's window to the register's own history and so delete the card's
+    whole exit. The harness purged, the tree fingerprint showed the edit on
+    disk, the delta was non-zero, and the mutant really did run. It was still a
+    survivor for a reason that has nothing to do with the property: in the
+    fixture the register never moves after `t = 0`, so `changed_mono` is
+    **`0.0`** - and `0.0 or x` is `x`. **The mutant was a no-op on that
+    stimulus.** Rewritten with an explicit `is None` test (+82 B) it is red on
+    four named checks.
+
+    Stale bytecode is a mutation that never *ran*. This is a mutation that ran
+    and could not *change the answer* on the data it was given, which is habit 4
+    exactly, one level up - and none of the three things a mutation report is
+    required to state (MUTATION.md's own list) can see it, because all three are
+    about the file rather than about the stimulus. Two rules:
+    * **Ask of every survivor what it would have had to change, and check that
+      the fixture reaches that value.** Here: "does any fixture have a non-zero
+      `changed_mono` at the moment `_open_window()` is called?" The answer was
+      no, and it is one line to ask.
+    * **Prefer a mutation that CANNOT be a no-op.** `or`, `and`, truthiness on
+      a numeric, a default argument and a `getattr` fallback all have a value at
+      which the mutant and the shipped tree coincide. An explicit comparison,
+      a constant swap or a deleted statement does not.
+
+    ⚠️ Note where this one was found: in the battery of a card whose whole
+    subject is a check that cannot reach the failure it names. **Second
+    instance in an instrument rather than in a check since habit 16, and the
+    third overall.**
+
+    ⚠️ **AND THE SAME CARD'S BATTERY CAUGHT A HABIT-22 COMMENT IN THE FIX
+    ITSELF, WHICH IS WHY THESE TWO BELONG NEXT TO EACH OTHER.**
+    `freshness.py` shipped `⚠️ RELEASE BEFORE GRADE, AND THE ORDER IS
+    LOAD-BEARING` with a worked reason. Swapping the two calls is **zero bytes**
+    and survived the battery: `_grade()` acts only when `|standing| >= move_w`
+    and `_release()` only when `|standing| < move_w`, so at most one can act on
+    any read and the order is **not observable**. Habit 22 says build X and
+    measure it; the battery is what builds X. The comment now states the
+    disjointness and the suite pins **that** - at 0, 100, 249, 250, 251 and
+    1300 W - rather than an order nothing depends on.
+
 And the mutation-table consequence: **a variant is not covered because a
 near-miss of it is.** DEV-02's table listed the *actuator* variant of the
 per-unit claim defect (`device`/`supervised` filed without `inv`), which the