Add bone sketch tool; extrude Both sides default; wasm CMake fixes

[trailcode]

Summary

• Add bone sketch tool (Shift+U / mode.add_bone): centers, radii, waist, optional holes and Bone A / Bone B nodes; commits outline then exits to Sketch inspection
• Extrude Options Both sides defaults to on (session sticky)
• Wasm: reliable Emscripten detect on modern emsdk; link FreeType from the OCCT wasm install

Fixes #255

Test plan

• Add bone: two centers, r1, r2, waist (Holes None) — outline commits; mode becomes Sketch inspection
• Holes One radius / Two radii; hole >= outer radius shows toast and ignores click
• Options Add center nodes off/on; Bone A / Bone B when on; prefs survive restart (gui.bone_*)
• Extrude: Both sides checked by default on fresh session
• Hotkey Shift+U / remappable mode.add_bone; toolbar icon present
• Desktop RelWithDebInfo or Release build; focused skt_tests if available
• Wasm: emcmake prints * C++ compiler: Emscripten and Using FreeType (wasm); link succeeds (no -lfreetype error)

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Note

Medium Risk
New sketch geometry and undo paths add moderate complexity; wasm CMake changes affect all Emscripten link/configure flows but are localized to build scripts.

Overview
Adds an Add bone sketch workflow (Shift+U / mode.add_bone): pick two centers, end radii, waist width, then optional holes. It builds a closed connecting-rod outline (tangent waist arcs), optional Bone A / Bone B center nodes, and returns to Sketch inspection after one commit instead of staying in the tool. Options Add center nodes and Holes persist as gui.bone_add_center_nodes and gui.bone_holes.

Supporting changes include Sketch::add_bone, bone geometry in utl_geom (make_bone_wire / compute_bone_geom), skt_tools_bone.cpp, sketch undo tweaks for promoted center nodes and names, and a documented Options layout (tool-specific block above Sketch options). Extrude sketch face now defaults Both sides to on for the session.

Wasm builds detect Emscripten via EMSCRIPTEN / CMAKE_SYSTEM_NAME (not only em++ in the compiler path), resolve FreeType from the OCCT wasm install, and link freetype so linking no longer fails on bare -lfreetype. Docs, changelog, icon, and default hotkeys/settings are updated accordingly.

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Cursor Bugbot has reviewed your changes using high effort and found 1 potential issue.

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Saved mode values shift

Medium Severity

Sketch_add_bone is inserted in the middle of EZY_MODE_LIST, but projects store mode as that enum’s integer. Files saved before this change reopen Dimension, Cross-section, Align shafts, and Set frame as the next tool (Dimension becomes Add bone). mode.h already notes that reordering needs a migration.

Additional Locations (2)

• src/gui.cpp#L3938-L3939
• src/gui.cpp#L4560-L4565

 

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