feat: show reconnect status in UI

src/main.js

@@ -1,4 +1,4 @@
-const { once } = window.__TAURI__.event;
+const { once, listen } = window.__TAURI__.event;
 const { invoke } = window.__TAURI__.core;
 
 const connectScreen = document.querySelector("#connect");
@@ -147,6 +147,26 @@ once("telemetry", (event) => {
   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;
+  const { btn } = sel;
+  if (status === "reconnecting") {
+    btn.textContent = "переподключение…";
+    btn.disabled = true;
+  } else if (status === "reconnected") {
+    btn.textContent = "✓";
+    btn.classList.add("device__connect--done");
+    btn.disabled = true;
+  } else if (status === "gave_up") {
+    btn.textContent = "подключить";
+    btn.classList.remove("device__connect--done");
+    btn.disabled = false;
+    selected[category] = null;
+  }
+});
+
 // --- Таймер ---
 const timerEl = document.querySelector("#timer");
 const timerBtn = document.querySelector("#timer-btn");