UX-77: Home's roll shares the peak room by room left to full, as control does

The cheap-run roll (cheaproll._Charge) shared the peak room by rating, control
shares it by room left to full (packshare.weights). With unequal levels one
battery's drawn block ended too early (rig F-1). The roll now uses
packshare.weights over the simulated levels, each battery capped at its rating,
a full one dropping out. test_ux77 gains two unequal-level walks and a
by-rating mutant; its walks model control's split by room too.

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

goodwe_controller/app/cheaproll.py

@@ -10,8 +10,10 @@ that goes on until the batteries are at their level or the cheap hours end.
 (`modetrade.energy()`, `priceruns.plan()`), until nothing is short or the next
 run does not follow on. `for_today()` reads the batteries at the level they
 will have by then: the charge power is the peak limit's room (peak aim minus
-the house, as `dayplan` counts it), shared by rating. Where that room is not
-known (no house profile or no aim), the rating is used.
+the house, as `dayplan` counts it), shared as control shares it: by room
+left to full (`packshare.weights()`), read again as the levels move, so a
+battery that fills drops out and its share goes to the others. Where that
+room is not known (no house profile or no aim), the rating is used.
 DECISIONS/UX-54-forecast-tab.md has the record.
 """
 
@@ -20,7 +22,7 @@ import math
 from dataclasses import dataclass
 from datetime import datetime, timedelta, timezone
 
-from . import arbitrage, dayplan, modetrade, priceruns
+from . import arbitrage, dayplan, modetrade, packshare, priceruns
 from .dayplan import EFF
 from .price import required_spread, uncertainty_of
 
@@ -85,7 +87,7 @@ def _ceil_slot(t):
 class _Charge:
     """The batteries' levels followed from `t0` while the chargers charge at
     the room the peak limit leaves: `min(sum of ratings, aim - house)`, shared
-    by rating, each stopping at `modetrade.charge_to()`."""
+    by room left to full as control does (`_shares()`), each stopping at `modetrade.charge_to()`."""
 
     def __init__(self, packs, t0, ceiling_pct, targets, aim_w, house):
         self.packs = {p.name: p for p in packs}
@@ -115,6 +117,34 @@ class _Charge:
                 self._charge(s, e, hour)
             self.t = nxt
 
+    def _shares(self, ch, w):
+        """Watts per charger: `w` shared by `packshare.weights()` over all
+        packs (room left to full, as control passes it), no charger above its
+        rating, the surplus going to the others. By rating where the room left
+        is not known (no capacity)."""
+        wt = packshare.weights(list(self.packs.values()), -1.0)
+        if wt is None:
+            wt = {p.name: abs(p.rating_w) for p in ch}
+        wt = {p.name: wt.get(p.name, 0.0) for p in ch}
+        cap = {p.name: abs(p.rating_w) for p in ch}
+        out, open_, left = {}, set(wt), float(w)
+        while open_:
+            tot = sum(wt[n] for n in open_)
+            if tot <= 0.0:
+                for n in open_:
+                    out[n] = 0.0
+                break
+            over = [n for n in open_ if left * wt[n] / tot > cap[n] + 1e-9]
+            if not over:
+                for n in open_:
+                    out[n] = left * wt[n] / tot
+                break
+            for n in over:
+                out[n] = cap[n]
+                left -= cap[n]
+                open_.discard(n)
+        return out
+
     def _charge(self, s, e, hour):
         ch = modetrade.chargers(list(self.packs.values()), self.ceil,
                                 targets=self.targets)
@@ -123,12 +153,13 @@ class _Charge:
             return
         w = self._room_w(hour, total)
         hrs = (e - s).total_seconds() / 3600.0
+        share = self._shares(ch, w)
         for p in ch:
             self.stops.setdefault(p.name, None)
             if not p.capacity_kwh:
                 continue
             to = modetrade.charge_to(p, self.ceil, self.targets)
-            kwh = w * abs(p.rating_w) / total * hrs / 1000.0 * EFF
+            kwh = share[p.name] * hrs / 1000.0 * EFF
             room = (to - p.soc) / 100.0 * float(p.capacity_kwh)
             if kwh <= 0.0:
                 continue