shutdown:
- add functions to read/write last encoder steps from nvs
- store encoder steps at shutdown
guide:
- add function to calculate layer count from cable length
- read last encoder-steps at startup
- if length >2m calculate layers, dont home
- home at move-to-zero when not done at startup
encoder library:
- add function to set encoder steps
control:
- read last encoder-steps at startup
- apply last steps if >2m
