Add custom light effect via external component

Recently I created a similar post but didn't reach my goal. This time I tried to use Perplexity to get my POC, which doesn't look too bad. But there must be a missing part.

I am using a ESP32, WS2812 LED strip and the neopixelbus library. I want (as a challenge) to write custom light effects not as lambda functions but with some C++ code.

I included my code as an external component but get the error "Unable to find effect with the name 'red_green_blink_effect'." while compiling.

All my code and config can be found in my github repo.

How can I solve this error to get this effect working (and finally shown in Home Assistant)?