Shrink NimBLE footprint to prevent stack overflow

Reduce BLE stack memory usage from ~68KB to ~52KB by disabling unused NimBLE roles (peripheral, broadcaster), limiting connections to 1, and reducing buffer counts for ACL, HCI events, and ATT entries. Remove unused cloud components (esp_insights, esp_rainmaker) that require unavailable server certificates. These changes prevent stack collision with the render shed, eliminating restart flaps on the reader device.

src/activities/ActivityManager.cpp

@@ -271,6 +271,10 @@ bool ActivityManager::bluetoothShouldBeActive() const {
   return std::any_of(stackActivities.begin(), stackActivities.end(), wants) || wants(currentActivity);
 }
 
+bool ActivityManager::bluetoothStartDeferred() const {
+  return currentActivity && currentActivity->deferBluetoothStart();
+}
+
 bool ActivityManager::skipLoopDelay() const { return currentActivity && currentActivity->skipLoopDelay(); }
 
 ScreenshotInfo ActivityManager::getScreenshotInfo() const {