Add Bluetooth connecting popup message

Add new translation string for displaying a popup message while Bluetooth connection is in progress.

src/activities/reader/EpubReaderActivity.cpp

@@ -874,7 +874,20 @@ void EpubReaderActivity::render(RenderLock&& lock) {
         bleinput::stop();
         built = buildSection();
         const bool bleOk = bleinput::ensureStarted();
-        LOG_INF("ERS", "BLE restart after build: begin=%d (auto-reconnect follows)", bleOk);
+        LOG_INF("ERS", "BLE restart after build: begin=%d", bleOk);
+        if (bleOk) {
+          // Show a connecting popup and give the bonded remote a moment to re-link so the
+          // user isn't left with an unresponsive remote and a silent pause. Bounded: a
+          // remote that needs a button press to re-advertise won't stall reading — it
+          // reconnects in the background after we return. The popup is drawn once (e-ink
+          // holds it) and the page render overwrites it when we resume.
+          GUI.drawPopup(renderer, tr(STR_BT_CONNECTING_POPUP));
+          const unsigned long deadline = millis() + 4000;
+          while (!BleHid.isConnected() && millis() < deadline) {
+            BleHid.poll();
+            delay(50);
+          }
+        }
       }
       if (!built) {
         LOG_ERR("ERS", "Failed to persist page data to SD");