MAINT-15: the balancing hold ends on time with no SoC reading

HOLD's time check moves into Maintenance._hold(), used by step() and
_no_soc(). A hold that loses its SoC now ends at hold_min, writes
last_completed and logs the same COMPLETE line. The 15 min HOLD line says
the hold still ends at its normal time. Behaviour with a reading is
unchanged (differential trace against db9e231).

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

goodwe_controller/app/maintenance.py

@@ -541,11 +541,29 @@ class Maintenance:
         events.append(msg)
         return MaintResult(IDLE, True, 0.0, False, events, failed=kind)
 
+    def _hold(self, now: datetime, events: list) -> MaintResult:
+        """HOLD for one tick, with or without a SoC reading (MAINT-15).
+
+        HOLD needs no level to end: it is reached only after the charge counted
+        as done (MAINT-13/14), so its end is a time check and nothing else.
+        """
+        elapsed = self._elapsed_min(now)
+        if elapsed >= self.cfg.hold_min:
+            self.store.set_time("last_completed", now)
+            self._enter(IDLE, now, events,
+                        f"maintenance: cycle COMPLETE ({elapsed:.0f} min hold) "
+                        "- handing back to the loop")
+            return MaintResult(IDLE, False, None, False, events)
+        # 0 W, not "do nothing": commanding zero is what stops the loop
+        # pulling the pack straight back down the moment it is full, which
+        # is exactly when the BMS needs it parked at the top.
+        return MaintResult(HOLD, True, 0.0, False, events)
+
     def _no_soc(self, now: datetime, phase: str, gate_open: bool,
                 events: list) -> MaintResult:
         """MAINT-14: one tick of a pack in a moving phase with no SoC reading.
 
-        HOLD is unchanged (0 W). DRAIN holds at 0 W, like HOLD, and its 12 h
+        HOLD stays at 0 W and ends at its normal time (MAINT-15). DRAIN holds at 0 W, like HOLD, and its 12 h
         timeout still runs. CHARGE keeps its timeout and wall backstop: out of
         time is a failure, except when the last SoC seen was within
         CHARGE_NEAR_FULL_PCT of the target, which counts as done (MAINT-13).
@@ -563,7 +581,7 @@ class Maintenance:
         if (not self._nosoc_said and (now - self._nosoc_since).total_seconds()
                 >= NOSOC_NOTE_MIN * 60):
             self._nosoc_said = True
-            tail = ("The hold waits for the level to come back."
+            tail = ("The hold still ends at its normal time."
                     if phase == HOLD else
                     f"The time limit of the {phase} still applies.")
             msg = (f"maintenance: no battery level for {NOSOC_NOTE_MIN} min. "
@@ -571,7 +589,7 @@ class Maintenance:
             _LOG.warning("%s", msg)
             events.append(msg)
         if phase == HOLD:
-            return MaintResult(HOLD, True, 0.0, False, events)
+            return self._hold(now, events)
         elapsed = self._elapsed_min(now)
         if phase == DRAIN:
             if elapsed > DRAIN_TIMEOUT_MIN:
@@ -736,16 +754,7 @@ class Maintenance:
             return MaintResult(CHARGE, False, None, True, events)
 
         if phase == HOLD:
-            if elapsed >= self.cfg.hold_min:
-                self.store.set_time("last_completed", now)
-                self._enter(IDLE, now, events,
-                            f"maintenance: cycle COMPLETE ({elapsed:.0f} min hold) "
-                            "- handing back to the loop")
-                return MaintResult(IDLE, False, None, False, events)
-            # 0 W, not "do nothing": commanding zero is what stops the loop
-            # pulling the pack straight back down the moment it is full, which
-            # is exactly when the BMS needs it parked at the top.
-            return MaintResult(HOLD, True, 0.0, False, events)
+            return self._hold(now, events)
 
         _LOG.error("maintenance: unknown phase %r, forcing idle", phase)
         events += self.abort(now, f"unknown phase {phase!r}")