Stabilize scrolling text updates

[Afiyetolsun]

Summary

• Render scrolling text frames from a stable copy of the current line.
• Reset and clamp the scroll cursor when text changes or the index gets out of range.
• Expand pinned Git dependency refs to full commit SHAs so current PlatformIO/Git can fetch them.

Fixes #58

Testing

• pio run -e nodemcu
• pio run -e esp3

[CODeRUS]

thank you