UX-77: Home draws today's grid charge for the hours control will really charge

The cheap run is sized at the full rating, so under the peak limit a battery is
still short when it ends, and control plans the next run then. Home drew only
the run under way. `cheaproll` rolls the run on the way control does
(`modetrade.energy()` + `priceruns.plan()` at each run end, lifted from
`dayview._levels()`), reading the levels at the charge power the peak limit
leaves (peak aim less the house, else the rating). `homeview.mode_runs()` and
`price_windows()` use it for today: the grid block, the Today line and the
chart's cheap bars run to where control stops, each battery's block to its
own stop. Display only: no control change.

test_ux54: today's grid block of the night-before scenario now follows the roll.

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

goodwe_controller/app/dayview.py

@@ -19,7 +19,8 @@ empty chart. DECISIONS/UX-54-forecast-tab.md has the record.
 import dataclasses
 from datetime import datetime, timedelta
 
-from . import arbitrage, dayplan, homeview as hv, modetrade, priceruns
+from . import arbitrage, cheaproll, dayplan, homeview as hv, modetrade
+from . import priceruns
 from . import solarfc
 from .daycurve import Batt, curve
 from .packmode import SOLAR_FIRST
@@ -210,25 +211,18 @@ def _levels(c, est, fc, trust, now, end, runs, floor, ceil, notes_b, shadow,
             arbitrage.threshold_eur_kwh(c.o),
             uncertainty_of(plan.read.product)
             | arbitrage.weather_uncertainty(True, c.solar_fc))
-        end_t = cheap.end
-        for _ in range(24):
-            ext = dataclasses.replace(rp, cheap=priceruns.Run(
+
+        def packs_at(end_t):
+            """The packs at the curve's level when a run ends at `end_t`."""
+            at = dataclasses.replace(rp, cheap=priceruns.Run(
                 cheap.start, end_t, cheap.mean_eur_kwh))
-            rt, lv = settle(ext, lv0)
-            at_end = [dataclasses.replace(packs[n], soc=v)
-                      for n, v in ((n, _level_at(lv.get(n, ()), end_t))
-                                   for n in lv) if v is not None]
-            e = modetrade.energy(at_end, floor, ceil, targets=targets)
-            if e[0] <= 1e-6:
-                break
-            new = priceruns.plan(
-                plan.read.points, end_t, required_eur_kwh=required,
-                charge_kwh=e[0], charge_kw=e[1], sell_kwh=0.0, sell_kw=0.0)
-            nxt = new.cheap
-            if nxt is None or not new.charge_useful() or nxt.start > end_t \
-                    or nxt.end <= end_t:
-                break
-            end_t = nxt.end
+            _rt, lv = settle(at, lv0)
+            return [dataclasses.replace(packs[n], soc=v)
+                    for n, v in ((n, _level_at(lv.get(n, ()), end_t))
+                                 for n in lv) if v is not None]
+        end_t = cheaproll.roll_end(
+            cheap, plan.read.points, packs_at, required=required,
+            floor_pct=floor, ceiling_pct=ceil, targets=targets)
         ext = dataclasses.replace(rp, cheap=priceruns.Run(
             cheap.start, end_t, cheap.mean_eur_kwh))
     rt, lv = settle(ext, lv0)