fix: telemetry live updates, input validation, connection race in UI

src/main.js

@@ -13,6 +13,7 @@ const groups = {
 
 const deviceCards = new Map(); // device_id -> li
 const selected = {}; // category -> { btn, card } подключённого датчика
+const pendingStatus = {}; // category -> status (пришёл до установки selected)
 
 function el(tag, className, text) {
   const node = document.createElement(tag);
@@ -108,6 +109,10 @@ async function connect(deviceId, btn, category, card) {
     btn.textContent = "✓";
     btn.classList.add("device__connect--done");
     selected[category] = { btn, card };
+    if (pendingStatus[category]) {
+      applyStatus(selected[category], category, pendingStatus[category]);
+      delete pendingStatus[category];
+    }
     if (category === "trainer") startBtn.disabled = false;
   } catch (e) {
     console.error(e);
@@ -140,17 +145,14 @@ once("battery", (event) => {
   if (card) card.querySelector(".device__head").append(batteryIcon(percent));
 });
 
-once("telemetry", (event) => {
+listen("telemetry", (event) => {
   const t = event.payload.telemetry;
   if (t.Power) setMetric("power-value", t.Power.watts);
   else if (t.Cadence) setMetric("cadence-value", Math.round(t.Cadence.rpm));
   else if (t.HeartRate) setMetric("hr-value", t.HeartRate.bpm);
 });
 
-listen("connection", (event) => {
-  const { category, status } = event.payload;
-  const sel = selected[category];
-  if (!sel) return;
+function applyStatus(sel, category, status) {
   const { btn } = sel;
   if (status === "reconnecting") {
     btn.textContent = "переподключение…";
@@ -165,6 +167,16 @@ listen("connection", (event) => {
     btn.disabled = false;
     selected[category] = null;
   }
+}
+
+listen("connection", (event) => {
+  const { category, status } = event.payload;
+  const sel = selected[category];
+  if (!sel) {
+    pendingStatus[category] = status;
+    return;
+  }
+  applyStatus(sel, category, status);
 });
 
 // --- Таймер ---
@@ -212,8 +224,12 @@ timerBtn.addEventListener("click", async () => {
 
 // --- Целевая мощность/каденс ---
 document.querySelector("#apply-btn").addEventListener("click", async () => {
-  const watts = Number(document.querySelector("#power-input").value);
-  const rpm = Number(document.querySelector("#cadence-input").value);
+  const powerRaw = document.querySelector("#power-input").value.trim();
+  const cadenceRaw = document.querySelector("#cadence-input").value.trim();
+  if (powerRaw === "" || cadenceRaw === "") return;
+  const watts = Number(powerRaw);
+  const rpm = Number(cadenceRaw);
+  if (!Number.isFinite(watts) || !Number.isFinite(rpm)) return;
   try {
     await invoke("set_target_power", { watts });
     await invoke("set_target_cadence", { rpm });