Updated PBR Overview (markdown)
mark v1.78-only stuff as "Coming in the v1.78 update" (water waves/subsurface, packed detail alpha, texture packer, global standard settings swaps, material upgrader, texture stripper), fix wave 4 default Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
texture packer docs: source-size resolution, normal/high quality compression by alpha, aniso + trilinear Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
update texture packer docs for the rewrite, drop sRGB notes from PBR page, document packed detail alpha Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
add PBR overview page Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>