Ripples were cleared every frame the player wasn't swimming, which
destroyed foot splash particles the same frame they were spawned.
Now particles expire naturally via their lifetime.
- Replace dark edge RGB on alpha-tested foliage with mip-4 average color
proportional to alpha (low alpha = low trust in original RGB)
- Raise foliage alpha cutoff to 0.4 and remove dither band for cleaner edges
- Disable depth test on insect particles so they don't vanish behind foliage
- Exempt dragonflies/butterflies/moths from foliage animation freeze
- Spawn dark point-sprite insects buzzing around cattails/reeds/kelp/seaweed
- Fix firefly M2 particles: exempt from alpha dampening and forced gravity
- Make water shoreline/crest foam more irregular with UV warping and bluer tint
- Play WaterFootstep splash sounds when wading in shallow water
- Spawn foot splash particles at water surface on each water footstep
- Reduce inland water wave amplitude from 0.18 to 0.08 for calmer lakes
