The compiled server runs Node's native ESM loader, where the CommonJS
namespace object nests the real exports under 'default', so
'import * as ClipperLib' left JoinType undefined and crashed with
offset. Match the existing vtracer pattern and require() the package
instead.
Trace results can now be inset (negative) or outset (positive) by a
pixel amount. Offset the outline and holes in opposite directions with
clipper-lib's miter joins, then recombine with a boolean difference so
holes grow on inset and shrink on outset. Collapsed shapes return an
empty outline; a split outline keeps the largest ring. Document the
parameter and the new dependency.
Add GET /trace which fetches an image, traces it into a vector shape, and returns the result BSON-encoded. Tracing is configurable via mode (alpha, bw, color) and format (shape, svg). The shape format parses the vtracer SVG into an outline/holes polygon matching @tts/mesh's Shape interface.