fix: build Universal Binary for Intel CPU support

[momenbasel]

Summary

• Added ARCHS: "arm64 x86_64" to project.yml build settings
• Updated CI workflow to pass ARCHS="arm64 x86_64" to xcodebuild
• This produces a Universal Binary that runs natively on both Intel and Apple Silicon Macs

Root Cause

The project had no explicit ARCHS setting, so Xcode defaulted to building only for the host architecture (arm64 on Apple Silicon). Intel Mac users got an incompatible binary.

Closes #7

[Copilot]

Pull request overview

This PR ensures the macOS app builds as a Universal Binary so it runs natively on both Intel (x86_64) and Apple Silicon (arm64) Macs, addressing Intel incompatibility reported in #7.

Changes:

• Added an explicit ARCHS: "arm64 x86_64" build setting in project.yml.
• Updated the GitHub Actions workflow build step to invoke xcodebuild with ARCHS="arm64 x86_64".

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
project.yml	Sets project-wide architectures to produce a universal macOS build.
.github/workflows/build.yml	Forces universal-arch build in CI via xcodebuild arguments.

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[Copilot]

Setting ARCHS at the global settings.base level applies to all configurations (including Debug), which can significantly slow local dev builds by always producing a universal binary. Consider scoping this to Release (or using XcodeGen per-config settings) so Debug can keep the default/active-arch behavior while Release produces the universal app.

[Copilot]

ARCHS is now set in project.yml, and the workflow also forces ARCHS on the command line. This duplication can drift over time; consider relying on the project setting (or alternatively removing it from project.yml and keeping CI as the single source of truth).