Add triple-tap lights-off and fix LED pin to D5

- Triple tap turns off LEDs; any subsequent tap or hold resumes the current show
- Change LED_DATA_PIN default from 6 to 5 across config, docs, and wiring diagram
- Fix Makefile upload to pass --input-dir so it uses the pre-built binary

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

arduino/cosplay_lights/config.h

@@ -18,7 +18,7 @@
 
 // -- Wiring --------------------------------------------------
 // Pin on the Arduino connected to the strip's DIN (data-in).
-#define LED_DATA_PIN  6
+#define LED_DATA_PIN  5
 
 // Clock pin — only needed for APA102/SK9822 strips.
 // #define LED_CLOCK_PIN 7
@@ -37,6 +37,7 @@
 // Uses INPUT_PULLUP — no external resistor needed.
 //   1 tap  → next show
 //   2 taps → previous show
+//   3 taps → lights off (any tap/hold resumes)
 //   hold   → reset to show 0 (blue breath)
 #define BUTTON_PIN  2