Release Octopus v1.0.0

[myunwang]

Summary

• promote the application version from 0.1.0 to 1.0.0
• add direct macOS and Windows download guidance to the README
• derive macOS bundle and archive versions from package.json
• give Windows release artifacts stable versioned names
• add a tag-driven GitHub Actions workflow that builds macOS ARM64 and Windows x64 packages, generates SHA-256 checksums, and publishes the GitHub Release only after both builds pass

Local validation

• npm test
• npm run package:mac
• macOS bundle version and packaged package.json both report 1.0.0
• codesign --verify --deep --strict
• ZIP integrity check
• local artifact: Octopus-1.0.0-mac-arm64.zip
• local SHA-256: 5c8fbfd66eadad62148efc5eb094a0250c43ee87827512e6b4e042637ac5f54e

After this PR is merged, pushing tag v1.0.0 will publish the macOS ARM64 ZIP, Windows x64 installer/ZIP, and SHA256SUMS.txt.