MAINT-11: start or stop the maintenance cycle per battery

maint_start and maint_abort take an optional unit. With two or more batteries
each Batteries card has Start cycle and Stop cycle buttons. One slot per site
stays: a start while a battery cycles is refused and names it (no queue). A
battery that is switched off, an unknown unit, and a stop on a battery that is
not cycling are refused with a plain message. A request with no unit is the
old call. The scheduler and the phase machine are unchanged.

Co-Authored-By: Claude <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Bdqr7PiaHcBnzPituu2yTC

goodwe_controller/app/static/app.js

@@ -336,6 +336,32 @@
     finally { packBusy = false; }
     await refresh(true);
   }
+  // MAINT-11: start or stop ONE battery's cycle. Two or more batteries only;
+  // the add-on refuses a second cycle and says which battery is cycling.
+  async function cycleAct(what, b) {
+    if (packBusy) return;
+    packBusy = true;
+    try {
+      const r = await fetch("action", { method: "POST", headers: { "Content-Type": "application/json" },
+                                        body: JSON.stringify({ action: what, unit: b.name }) });
+      const j = await r.json().catch(() => ({}));
+      const own = j.code && t("batteries.cycle." + j.code);
+      if (!r.ok) toast(own ? say(own.description, { name: j.unit || b.name }) : (j.error || t("toast.failed")));
+      else toast(say(t("batteries.cycle.toast." + (what === "maint_start" ? "started" : "stopped")), { name: b.name }));
+    } catch (e) { toast(t("toast.failed")); }
+    finally { packBusy = false; }
+    await refresh(true);
+  }
+  function cycleButtons(b, i) {
+    const ask1 = (key, what) => () => {
+      const w = t("batteries.cycle." + key);
+      ask({ name: say(w.name, { name: b.name }), description: say(w.description, { name: b.name }), yes: w.yes },
+          () => cycleAct(what, b));
+    };
+    return h("div", { class: "cyc", style: "display:flex;gap:8px;flex-wrap:wrap;margin-top:10px" },
+      h("button", { type: "button", class: "btn", id: "bcs-" + i, onclick: ask1("start_dialog", "maint_start") }, t("batteries.cycle.start")),
+      h("button", { type: "button", class: "btn danger", id: "bca-" + i, onclick: ask1("abort_dialog", "maint_abort") }, t("batteries.cycle.abort")));
+  }
   function onSwitch(b, i, where, lid) {
     const sw = h("button", { type: "button", class: "switch", role: "switch", id: "bsw-" + where + i,
                              "aria-checked": String(b.use), "aria-labelledby": lid,
@@ -370,7 +396,8 @@
         h("dt", {}, t("batteries.level")), h("dd", {}, lvl + stored),
         h("dt", {}, t("batteries.now")), h("dd", {}, b.now),
         h("dt", {}, t("batteries.today")), h("dd", {}, todayLines(b)),
-        h("dt", {}, t("batteries.why")), h("dd", { class: "muted" }, b.why || "–")));
+        h("dt", {}, t("batteries.why")), h("dd", { class: "muted" }, b.why || "–")),
+      S.batteries.length > 1 ? cycleButtons(b, i) : null);
   }
   function simpleRow(b, i) {
     const lid = "bsname-" + i;