SWEEP: sweep from the picked path end; kernel run faces and placed ends

- An open path is swept from its end nearest the pick point (in plan), as
  the reference does; the record keeps the original path and the placed
  frame marks the start.
- Kernel from ramox81/cadkernel 1df75f5: one face per path run for
  twisted, scaled and spline sweeps, placed records swept from the placed
  end, end caps without pcurves.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Cargo.toml

@@ -181,3 +181,7 @@ harness = false
 [[test]]
 name = "integration"
 path = "tests/integration.rs"
+
+[patch."https://github.com/HakanSeven12/opencadkernel.git"]
+opencadkernel = { git = "https://github.com/ramox81/cadkernel.git", rev = "1df75f5" }
+opencadkernel-constraints = { git = "https://github.com/ramox81/cadkernel.git", rev = "1df75f5" }