World props: wild plants

Model and bake the 113 sprites of group flora of the world-props order (assets/requests/world-props/flora.md, brief assets/requests/world-props.md) on their own branch. Done when every sprite of the list is in assets/manifest.d/world_flora.toml, baked and reviewed on a gallery sheet.

Done (2026-10-19): all 113 baked (tools/blender/models/world_flora/, eight family scripts on a shared flora_kit.py) and reviewed on gallery sheets. Bushes, saplings, young trees, palms, juniper, ferns and the swamp tree come from the Quaternius packs; everything else is texel voxels on the lattice. branch_fallen is baked with its 4 facings but one variant (ordered with 2): uo-baker takes variants only for directions = 1.