- coordinates.js: scans posList/pos text directly; plain decimals up to 15
  digits are converted exactly (integer / power of ten, bit-identical to
  parseFloat), everything else goes through parseFloat
- triangulate.js (moved out of citygml.js): triangles and quadrilaterals
  without holes are split directly, concave ones at the reflex corner;
  self-intersecting, degenerate or holed polygons and corners that coincide
  in libtess's 2D projection stay with libtess

On 156 test files vertex counts and colours are identical to before; total
area differs by at most 1.7e-6 (other diagonal of non-planar quads).
274 MB LoD2 file: 7.2 s -> 5.8 s in Node.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>