noBS CAD Bevy desktop pre-alpha — macOS arm64 + Windows x64

This pre-alpha desktop build contains the native Bevy viewport release merged by PR #28 and is intended for hands-on testing.\n\nBuilt from commit d488c21.\n\nDownloads:\n- macOS Apple silicon: open the DMG and drag noBS CAD to Applications. This development build is ad-hoc signed and is not notarized.\n- Windows x64: extract the portable ZIP and run noBS-CAD.exe. This development build is not code-signed.\n\nValidation:\n- macOS arm64 architecture, package signing integrity, and launch smoke test passed.\n- Windows packaged native viewport verification passed.\n\nSHA-256:\n- macOS DMG: f8d6b60b0491b186445f174cda80d08ee6d7bb0ea5b124f4bc2f90021b37411b\n- Windows ZIP: 64e87a3f9029685f310587e39e3a4d98bbf98d1e8f996a0a144e6ea4feee579d\n\nThis is pre-alpha software. Keep STEP backups of important work and report crashes or confusing behavior through GitHub Issues.