entities_centroid summed the f32 points (double-single HIGH half) alone, so
at UTM scale (~5.7e6) it both quantized each term ~0.5 m and lost low bits
across the running total — drifting the paste base and PASTEBLOCK's block
base metres off, which placed the wrapped block at the wrong spot/scale.
It now reconstructs each vertex's absolute f64 from points + points_low and
accumulates in f64. clipboard_centroid is DVec3; the PASTECLIP commit delta
is fully f64; define_block_from_owned_entities takes an f64 base so the
block-local fold (Translate(-base)) stays precise. The interactive ghost
anchors (PasteCommand, InsertBlockCommand) still take the f32 cast — display
only; the committed geometry is f64.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>