You're most welcome! Glad this is what you were looking for.

To change direction, you'll just have to flip the direction,
So these 2 for-loops:

      for(int i=0; i<NUM_LEDS; i++) {
        leds.setRGB(255,50,0);
        FastLED.show();
        delay(10);
      }
      
      delay(200);
      
      //setAll(0,0,0); 
      for(int i=0; i<NUM_LEDS; i++) {
        leds.setRGB(0,0,0);
        FastLED.show();
        delay(10);
      }

could become:

      for(int i=0; i<NUM_LEDS; i++) {
        leds.setRGB(255,50,0);
        FastLED.show();
        delay(10);
      }
      
      delay(200);
      
      //setAll(0,0,0); 
      for(int i=0; i<NUM_LEDS; i++) {
        leds.setRGB(0,0,0);
        FastLED.show();
        delay(10);
      }

(untested)

So combined, using 2 buttons (left and right), this may work (again: untested);

#include "FastLED.h"
#include <EEPROM.h>
#define NUM_LEDS 60 
#define blinkcount 5
CRGB leds;
#define PIN 6 
#define BUTTONLEFT  2
#define BUTTONRIGHT 3
byte selectedEffect   = 0;
int  buttonStateLeft  = 0;
int  buttonStateRight = 0;
bool AButtonPressed   = false;
void setup()
{
  FastLED.addLeds<WS2811, PIN, GRB>(leds, NUM_LEDS).setCorrection( TypicalLEDStrip );
  pinMode(BUTTONLEFT,  INPUT);
  pinMode(BUTTONRIGHT, INPUT);
}
void loop() { 
  buttonStateLeft  = digitalRead(BUTTONLEFT);
  buttonStateRight = digitalRead(BUTTONRIGHT);
  AButtonPressed = (buttonStateLeft == HIGH) || (buttonStateRight == HIGH);
  
  if (AButtonPressed) {
    
    if(buttonStateLeft == HIGH) {
      DirectionCorrection = 0;
    }
    else {
      DirectionCorrection = NUM_LEDS;
    }
    
    for(int blink=0; blink<blinkcount; blink++) {
      
      for(int i=0; i<NUM_LEDS; i++) {
        if(buttonStateLeft == HIGH) {
          leds.setRGB(255,50,0);
        } else {
          leds.setRGB(255,50,0);
        }
        FastLED.show();
        delay(10);
      }
      
      delay(200);
      
      // Cleanup swipe after swipe
      //setAll(0,0,0);
      for(int i=0; i<NUM_LEDS; i++) {
        if(buttonStateLeft == HIGH) {
          leds.setRGB(0,0,0);
        } else {
          leds.setRGB(0,0,0);
        }
        FastLED.show();
        delay(10);
      }
      
      delay(200);
      
    }
    setAll(0,0,0);
  }
  else {
    setAll(0,0,0);
  }
}
// Set all LEDs to a given color and apply it (visible)
void setAll(byte red, byte green, byte blue) {
  for(int i = 0; i < NUM_LEDS; i++ ) {
    leds.setRGB(red, green, blue); 
  }
  FastLED.show();
}

Hope this helps ... and if you're done with your Vespa, please feel free to share the end result here