Hide sketch-from-face profile wire outside sketch modes

[trailcode]

Summary

• Fix the dark-red sketch from face originating-face wire so it follows set_show_edges and is hidden when Occt_view::on_mode leaves sketch mode (e.g. after Revolve returns to Normal).
• Document the behavior in docs/usage-sketch.md, src/doc/sketch.md, and CHANGELOG.md.

Closes #233

Test plan

• Build EzyCad (or EzyCad_lib) and run relevant sketch tests if convenient.
• Manual: Create sketch from planar face on a solid → confirm dark-red boundary while in sketch inspection/tools.
• Manual: Escape / switch to Normal → red profile wire is gone; sketch edges/faces stay hidden as before.
• Manual: Re-enter sketch inspection → wire returns (sketch still visible in Sketch List).
• Manual: Optional Revolve then return to Normal → no leftover red profile on the solid.
• Docs: skim usage-sketch.md Create Sketch from Planar Face section and changelog entry.

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