OPT-11 P4: solar forecast and day plan

A Home Assistant solar forecast (Forecast.Solar, Solcast or Open-Meteo
shapes) and the add-on's own hourly house use decide, before each cheap
run, whether the sun will fill each battery before the expensive hours.
Leftover solar then buys from the grid only the shortfall; Cheap hours only
skips the part the sun covers; Solar first never grid-charges. No, stale or
failed forecast: P3 option A exactly (12 digests pinned from 5a4cdc2).

Replay (16 recorded days, forecast errors from Elia's day-ahead BE solar):
year-earlier prices P4 19.15 vs P2 19.33 / option A 19.44 / old trade 18.14;
real 2026 prices P4 29.19 vs 32.26 / 32.01 / 31.40 EUR net.

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

goodwe_controller/app/static/app.js

@@ -403,6 +403,9 @@
     else $("#batt-banner").replaceChildren();
     keepFocus(() => {
       $("#bcards").replaceChildren(...S.batteries.map(batteryCard));
+      // OPT-11 P4: the solar forecast line under the cards.
+      const sl = $("#batt-solar"), line = modes && S.solar ? S.solar.line : "";
+      if (sl) { sl.textContent = line || ""; sl.hidden = !line; }
       if (simpleHost && simpleHost.isConnected) {
         simpleHost.replaceChildren(...(modes ? S.batteries.map(simpleRow)
           : [h("p", { class: "small muted", style: "margin:4px 0" }, t("batteries.modes_off.name") + ". " + t("batteries.description"))]));