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"))]));

goodwe_controller/app/static/index.html

@@ -101,6 +101,7 @@
     <a class="btn" href="#settings" data-t="batteries.settings"></a>
   </div>
   <div id="bcards"></div>
+  <p class="small muted" id="batt-solar" hidden></p>
   <details class="grp" id="batt-how" hidden>
     <summary><span class="grow"><strong data-t="batteries.how.name"></strong><span class="small muted gdesc" data-t="batteries.how.description"></span></span><span class="chev" aria-hidden="true">&#8250;</span></summary>
     <div class="body small">

goodwe_controller/app/static/settings.js

@@ -446,7 +446,17 @@
       e.textContent = ok ? e.dataset.kwNote.replace("{kw}", window.UX13.kw(mp.peak_w) + " kW") : "";
     });
   }
+  // OPT-11 P4: the solar forecast card shows the add-on's forecast line.
+  function fillSolar() {
+    const st = window.UX13.status();
+    const line = st && st.solar ? st.solar.line : "";
+    document.querySelectorAll("#simple [data-solar-note]").forEach((e) => {
+      e.textContent = line || "";
+      e.hidden = !line;
+    });
+  }
   document.addEventListener("ux13:status", fillNotes);
+  document.addEventListener("ux13:status", fillSolar);
   function simpleField(f) {
     const row = fieldRow(f, null, "simple");
     row.querySelector(".head").append(chip(f.applies));
@@ -458,6 +468,7 @@
       const help = row.querySelector(".help");
       if (help) help.textContent = n.description;
     }
+    if (f.note === "forecast") row.append(h("div", { class: "small muted", "data-solar-note": "", hidden: true }));
     return h("div", { class: "card" }, row);
   }
   function renderSimple() {