Remove all LED pulsing - returning to stable baseline

Pulsing code was causing crashes (FastLED.show() RMT conflict with USB).
Removed:
- update() is now empty no-op (was calling mux_ptr->show() every 33ms)
- Removed set_bpm(), beat_interval_ms, bpm serial command
Kept:
- Per-pad LED colors with dim off state (working fine)
- All button/MIDI/expression pedal functionality

include/led_stub.h

@@ -33,7 +33,6 @@ private:
     static const uint8_t NUM_LEDS = 10;
     LedState led_states[NUM_LEDS];
     bool initialized;
-    uint32_t beat_interval_ms = 500;
     
 public:
     DefaultLedStub();
@@ -45,5 +44,4 @@ public:
     void update() override;
 
     void set_mux(PixelStompMux* mux);
-    void set_bpm(uint16_t bpm);
 };

src/led_stub.cpp

@@ -299,36 +299,5 @@ void DefaultLedStub::flash_activity() {
     // LED feedback is handled directly by set_led_state().
 }
 
-void DefaultLedStub::set_bpm(uint16_t bpm) {
-    if (bpm == 0) bpm = 120;
-    beat_interval_ms = 60000 / bpm;
-    Serial.printf("[LED] Pulse BPM set to %d (%dms)\n", bpm, beat_interval_ms);
-}
-
 void DefaultLedStub::update() {
-    if (!initialized || !mux_ptr) return;
-
-    uint32_t now = millis();
-    static uint32_t last_pulse_update = 0;
-
-    if (now - last_pulse_update < 33) return;
-    last_pulse_update = now;
-
-    float phase = (now % beat_interval_ms) / (float)beat_interval_ms;
-
-    // Instant-on at beat, quick fade to 0 by phase 0.25
-    float pulse = 1.0f - phase * 4.0f;
-    if (pulse < 0.0f) pulse = 0.0f;
-
-    // Active LEDs keep their last set_led_state() color — don't override.
-    // Pixel 6 pulses only when not active (visual metronome for timing).
-    if (!led_states[6].active) {
-        float brightness = 0.3f + 0.7f * pulse;
-        uint32_t base = pad_base_colors[6];
-        uint8_t r = (uint8_t)(((base >> 16) & 0xFF) * brightness);
-        uint8_t g = (uint8_t)(((base >> 8) & 0xFF) * brightness);
-        uint8_t b = (uint8_t)((base & 0xFF) * brightness);
-        mux_ptr->set_led_color(6, r, g, b);
-        mux_ptr->show();
-    }
 }

src/main.cpp

@@ -89,13 +89,6 @@ void handle_serial_command(const String& cmd) {
     } else if (cmd == "exp") {
         Serial.printf("[CMD] EXP ADC=%d MIDI=%d\n",
                       exp_pedal.get_raw(), exp_pedal.get_value());
-    } else if (cmd.startsWith("bpm ")) {
-        uint16_t bpm = cmd.substring(4).toInt();
-        if (bpm >= 20 && bpm <= 300) {
-            led_driver.set_bpm(bpm);
-        } else {
-            Serial.println("[CMD] BPM must be 20-300");
-        }
     } else if (cmd == "usb") {
         Serial.printf("[CMD] USB mounted: %s\n", TinyUSBDevice.mounted() ? "YES" : "NO");
         Serial.printf("[CMD] USB ready: %s\n", TinyUSBDevice.ready() ? "YES" : "NO");
@@ -140,7 +133,6 @@ void handle_serial_command(const String& cmd) {
         Serial.println("  red/green/blue - solid colour");
         Serial.println("  pixel0/pixel1 - single pixel test");
         Serial.println("  exp        - expression pedal ADC/MIDI value");
-        Serial.println("  bpm <n>    - set LED pulse tempo (20-300, default 120)");
         Serial.println("  usb        - USB connection status and descriptor info");
         Serial.println("  gpiotest   - raw GPIO pin diagnostic");
         Serial.println("  rawled     - bit-bang WS2812 (no library)");
@@ -364,9 +356,6 @@ void setup() {
     Serial.println("[INIT] Initializing Expression Pedal...");
     exp_pedal.begin();
     
-    Serial.println("[INIT] Setting LED pulse tempo...");
-    led_driver.set_bpm(120);
-
     Serial.println("[INIT] Registering MIDI callbacks...");
     controller.begin();