Fix USB MIDI, add GPIO for switches and LEDs

- Remove TinyUSBDevice.begin() conflict with Arduino core
- Switch stub now reads GPIO with debounce (pins 1-10)
- LED stub now drives GPIO pins (pins 11-20) with startup animation
- All pins printed to console on init

src/switch_stub.cpp

@@ -1,10 +1,14 @@
 #include "switch_stub.h"
 #include <Arduino.h>
 
+static const uint8_t SWITCH_PINS[10] = {
+    1, 2, 3, 4, 5, 6, 7, 8, 9, 10
+};
+
 DefaultSwitchStub::DefaultSwitchStub() : initialized(false) {
     for (int i = 0; i < NUM_SWITCHES; i++) {
         switch_states[i].id = i;
-        switch_states[i].gpio_pin = 0;
+        switch_states[i].gpio_pin = SWITCH_PINS[i];
         switch_states[i].current_state = false;
         switch_states[i].previous_state = false;
         switch_states[i].last_change_time = 0;
@@ -13,20 +17,46 @@ DefaultSwitchStub::DefaultSwitchStub() : initialized(false) {
 }
 
 void DefaultSwitchStub::begin() {
+    for (int i = 0; i < NUM_SWITCHES; i++) {
+        pinMode(switch_states[i].gpio_pin, INPUT_PULLUP);
+    }
     initialized = true;
-    Serial.println("[SW] Stub initialized (GPIO pins not configured yet)");
+    Serial.printf("[SW] Initialized %d switches on GPIOs: ", NUM_SWITCHES);
+    for (int i = 0; i < NUM_SWITCHES; i++) {
+        Serial.printf("%d ", switch_states[i].gpio_pin);
+    }
+    Serial.println();
 }
 
 bool DefaultSwitchStub::is_pressed(uint8_t switch_id) {
     if (!initialized || switch_id >= NUM_SWITCHES) {
         return false;
     }
-    return switch_states[switch_id].current_state;
+
+    SwitchState& sw = switch_states[switch_id];
+    bool raw = (digitalRead(sw.gpio_pin) == LOW);
+    uint32_t now = millis();
+
+    if (raw != sw.previous_state) {
+        sw.last_change_time = now;
+    }
+
+    if ((now - sw.last_change_time) >= sw.debounce_time) {
+        if (raw != sw.current_state) {
+            sw.current_state = raw;
+        }
+    }
+
+    sw.previous_state = raw;
+    return sw.current_state;
 }
 
 void DefaultSwitchStub::configure_switch(uint8_t switch_id, uint8_t gpio_pin) {
     if (switch_id >= NUM_SWITCHES) return;
     switch_states[switch_id].gpio_pin = gpio_pin;
+    if (initialized) {
+        pinMode(gpio_pin, INPUT_PULLUP);
+    }
     Serial.printf("[SW] Switch %d configured to GPIO %d\n", switch_id, gpio_pin);
 }