fix(circle): use kernel tangent solutions

Route tangent-tangent-radius construction through cadkernel so enclosing and external tangency share one geometry implementation.

Refs #814

Cargo.lock

@@ -878,7 +878,7 @@ checksum = "fc652a48c352aef3ea3aed32080501cf3ef6ed5da78602a020c991775b0aff04"
 [[package]]
 name = "cadkernel"
 version = "0.1.0"
-source = "git+https://github.com/HakanSeven12/cadkernel.git?rev=2af87ad#2af87adf3e3234fd9e8df1bfe01faf7e2b6333d1"
+source = "git+https://github.com/HakanSeven12/cadkernel.git?rev=eda1263#eda1263da23c1b18e7593151a277a0593bb317ef"
 dependencies = [
  "acadrust",
  "cavalier_contours",