Fix for ESP32-S3-WROOM-1: safe GPIO pins, serial flush, delays

- Switch pins: 2-7, 15-18 (avoids USB 19/20, PSRAM 26-32, JTAG 34-37)
- LED pins: 38-42, 45-48, 21 (high GPIOs, no special functions)
- Add Serial.flush() after init messages
- Increase startup delays for reliable serial output
- Board: esp32-s3-devkitc-1-n16r8

src/main.cpp

@@ -26,17 +26,24 @@ void midi_task(void* parameter) {
 
 void setup() {
     Serial.begin(115200);
-    delay(1000);
+    delay(2000);
     
     Serial.println("=================================");
     Serial.println("  Loopy MIDI Controller v0.1");
     Serial.println("  Phase 1: USB MIDI");
+    Serial.println("  Board: ESP32-S3-WROOM-1");
     Serial.println("=================================");
     
+    Serial.println("[INIT] Starting LED startup animation...");
     led_driver.begin();
+    
+    Serial.println("[INIT] Initializing switches...");
     switch_driver.begin();
     
+    Serial.println("[INIT] Initializing USB MIDI...");
     midi_transport.begin();
+    
+    Serial.println("[INIT] Registering MIDI callbacks...");
     controller.begin();
     
     xTaskCreatePinnedToCore(
@@ -51,8 +58,9 @@ void setup() {
     
     Serial.println("=================================");
     Serial.println("  All systems ready");
-    Serial.println("  Waiting for USB connection...");
+    Serial.println("  Waiting for USB MIDI host...");
     Serial.println("=================================");
+    Serial.flush();
 }
 
 void loop() {