Add Twist option to sketch extrude

[trailcode]

Summary

Adds a Twist option to the sketch face Extrude tool. When enabled, the extruded profile rotates about the extrude axis as it is pulled, producing twisted solids while preserving face holes.

Closes #227.

Changes

• Interaction: new Twist checkbox in Extrude Options; two-phase flow (drag/Tab to lock height, then drag to set twist angle about the face centroid; Shift+Tab types exact degrees). With Both sides, the mid-plane stays fixed and each end twists +/- half the angle.
• Geometry: twisted bodies use ruled BRepOffsetAPI_ThruSections with CheckCompatibility(false) and intermediate sections (~45 deg spacing); hole wires are lofted and cut so face bores survive the twist. Straight MakePrism is retained when twist is ~0.
• Preview + annotation: dense-face fast preview also rotates face copies during the Twist phase; the height length dimension is cleared once height is locked and replaced with an angle annotation (degrees) centered on the extruded front face.

Files Changed

• src/shp_extrude.cpp / src/shp_extrude.h
• src/gui_mode.cpp, src/gui_occt_view.cpp, src/gui.cpp
• src/utl_geom.cpp / src/utl_geom.h, src/utl_types.h
• tests/skt_tests.cpp, tests/skt_test_fixture.cpp / .h
• docs/usage.md, docs/usage-settings.md, src/doc/{gui,shape,sketch,utility}.md, CHANGELOG.md

Related

• Issue: Sketch extrude: add Twist option #227

Test Plan

• Build EzyCad_lib and EzyCad_tests.
• EzyCad_tests --gtest_filter=Sketch_test.ExtrudeSketchFace* (includes new ExtrudeSketchFace_Twist_solid and ExtrudeSketchFace_Twist_both_sides_solid).
• Manual: twist a sprocket-like face; verify teeth and holes are preserved, both-sides is symmetric, and the angle annotation reads correctly.
• Docs build and review rendered pages.

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