Jumping Bug Causes Gravity Reversal

## Description
There is a known bug where attempting to jump occasionally causes gravity to reverse or behave incorrectly, resulting in unpredictable player movement.

## Steps to Reproduce
- Attempt to jump under certain conditions (exact trigger unclear)
- Player experiences inverted or reversed gravity behavior

## Expected Behavior
- Jumping should consistently apply upward force and return the player to normal gravity

## Status
- Known issue (acknowledged during submission)

## Notes
- Likely related to physics, gravity scale, or state transitions
- Should be investigated before any future polish or expansion