Converted entity materials to new fade shader
Implemented visibility system
Refactored per-instance entity code to run inside monobehavior on entity instances
Created state machine AI for enemy ships with basic patrol and combat routines
Removed legacy AI code (controller item behaviors)
Added automatic trigger group assignment for matched weapons
Created ship collision system
Created shield VFX and colliders
Minimap works again
Stardust density is now proportional to gravity depth
Generated zones are double the size and better distributed
Orbital hierarchy actually working now (!)
Station start position actually orbits something now
Max gravity strength remapped to infinity (zone boundary is properly impassable now)
