Three commit helpers narrowed a typed/picked point back to f32 before it
reached the persisted entity, so the coordinate was quantized to the f32
grid (worse at large/UTM extents):
- Scene::create_block_from_entities took the base point as glam::Vec3, so
the block's local-space translation and the replacement INSERT's
insert point were f32. Param is now DVec3 (matching the sibling
define_block_from_owned_entities); the command_driver handler no longer
downcasts with as_vec3().
- The MTEXT and TEXT in-place editors stored `pos` as Vec3 and built the
committed insertion_point from it, quantizing a new label's position
and re-quantizing an existing one on edit. Both `pos` fields are now
DVec3.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
553b91015f