The platform collision check in resolve_tilemap_y required vel.y > 0
(strictly falling), so once landing zeroed vel.y the check would fail
next frame. Gravity would add a tiny downward velocity, the platform
would catch it again, and the cycle repeated — causing animation
jitter and repeated landing dust particles.
Change the condition to vel.y >= 0 so platforms resolve when resting.
Extend the ground-stick anti-flicker probe to also detect TILE_PLATFORM
tiles (was TILE_SOLID only), with a proximity guard to preserve
jump-through-from-below behavior.
WIND directive in .lvl files sets a constant horizontal force (px/s^2)
that pushes entities, projectiles, and particles. Positive is rightward.
Wind is applied as acceleration in physics_update() (halved on ground),
directly to projectile and particle velocities, and as a gentle position
drift on flyers. Entities with gravity_scale=0 (drones, spacecraft) are
unaffected. Levels default to no wind when the directive is absent.
