feat: preserve body history and placed modelling workflows

Record ownership transfers in the timeline so earlier Join/Cut membership,
world placement, machining data and styles survive component moves, edits,
independent copying, undo and reopening. Preserve pending positions in history
snapshots and keep constructor transfers ordered during feature redefinition.

Retain shallow sheet pockets and exact planar intersection islands through
unfold/refold, with depth-aware flat previews and DXF export. Store explicit
3D wire coordinate spaces and migrate known legacy provenance without moving
saved points or analytic fits.

Infer unique eligible cylindrical Emboss targets, align Revolve manipulators
with actual extent geometry, and discard obsolete preview errors after input
correction. Certify constructed and immutable imported face styles using exact
source metadata while preserving legacy face names. Upgrade designs to format10
with bounded validation and geometry-preserving legacy migration.

docs/book/src/guide/sketching.md

@@ -29,6 +29,18 @@ Smooth open offsets can be offset again, including bounded refinement after a so
 A closed offset uses a natural cubic spline whose seam can have different end tangents;
 offsetting that result again is refused when the seam has no unique normal.
 
+Enable **3D Sketch** in the Sketch Palette to draw lines, fit splines and points off the plane.
+New 3D geometry follows its sketch's component placement, including the selected occurrence
+and pending position changes. Click a drawn fit point to show its move triad; its arrows move
+along world X, Y and Z. Scripts also supply world coordinates to `sketch.line3d`,
+`sketch.spline3d`, `sketch.point3d` and `sketch.move3d`. Activate the desired occurrence before
+editing an explicit sketch belonging to a component with multiple placements.
+
+Older drawn or detached 3D wires keep their saved world positions. Included and surface-linked
+wires with an explicit component marker keep that meaning after the link is broken. Old files
+whose links became lost after an incorrectly scoped cross-component refresh may require a
+fresh link once the source is available; their stored point values are preserved on opening.
+
 ## Constraints and dimensions
 
 The solver is SolveCraft's own (damped Gauss–Newton with degree-of-freedom analysis). Constraints: