Add a gamerule for projectile momentum or let vehicles bypass 2-tick grace.

The recent changes to projectile physics—specifically the 2-tick delay before a projectile registers a collision margin and the strict 3D hitbox-based splash potion scaling—have severely impacted the vehicle and modding community. While these fixes make sense for preventing players from accidentally hitting themselves with their own arrows or pearls under normal circumstances, they completely break mechanics when throwing items from moving entities (like fast boats, minecarts, or custom modded vehicles like planes). Because the projectile passes cleanly outside the vehicle's hitbox before the 2-tick window activates, it is impossible to apply splash effects to your own transport platform while in motion. I request that Mojang either: 1. Introduce a new gamerule (e.g., /gamerule projectileInertia) that allows server admins and map makers to toggle whether projectiles inherit full velocity from the moving entity that threw them. 2. Adjust the code so that projectiles thrown by a passenger inside a vehicle can still immediately interact with that specific vehicle's bounding box, bypassing the 2-tick grace period. This would preserve the intended vanilla bug fix while restoring vital functionality for technical builders, minigame creators, and the modding ecosystem.