Complete Surface: plane surfaces, extrusions, isolines and moves

Adds SurfaceFromProfile and Extrude kernel operations (doc.solids.surface and
doc.solids.extrude), accepts surfaces in Transform, and maps Surface with
editable isolines. Fixes a real bug found by the test: the surface kind field
overwrote the entity-type kind key in Python dicts, so it is exposed as
surface_kind, with a catalog test guarding against name collisions.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

plugins/opencad-python/README.md

@@ -94,7 +94,7 @@ The host-owned catalog classifies all 48 entity variants and tracks every
 traced field, including fields marked `unmapped`. Query it with
 `doc.coverage()` or `doc.coverage("Line")`; each row includes source field,
 type, access, and current validation status. Geometry edits remain limited to
-the 41 mapped kinds.
+the 42 mapped kinds.
 For any entity, `entity.snapshot` returns a detached dictionary of its raw
 CAD fields, including `snapshot["common"]` and kind-specific nested values.
 It can inspect an unmapped kind; editing the dictionary does