Add GitHub Actions CI build on every PR

[rayl15]

What & why

Until now nothing compiled a PR before a human read it; the only check was CodeRabbit. This adds a GitHub Actions workflow that builds the app and its test target on every pull request and push to main, plus a CI badge in the README.

• xcodebuild build-for-testing for generic/platform=iOS with code signing off. That proves the code compiles against the iOS SDK without certificates, and it matches how the app is actually run (on a phone; the simulator can't do Bluetooth or on-device MLX).
• Runs on the standard macos-26 runner, which is free for public repositories. Larger runners are billed even on public repos, so the job stays on the plain label.
• Copies the two gitignored config files from their .example versions, the same two the README asks contributors to create; the placeholder values are enough to compile.
• Passes -skipPackagePluginValidation and -skipMacroValidation: mlx-swift ships a build plugin (CudaBuild) and mlx-swift-lm uses Swift macros, and Xcode refuses both until a human approves them.
• Caches SwiftPM checkouts (MLX, Kokoro, Meta DAT are the slow part) keyed on project.pbxproj + project.yml, since Package.resolved is gitignored.
• Pins Xcode via DEVELOPER_DIR so an image update can't change the SDK under a PR.
• Uploads the .xcactivitylog files when the build fails.

What the first runs showed

• Run 1 failed on the unapproved CudaBuild plugin; run 2 on the missing Config.swift. Both are fixed in this branch and documented in the workflow comments.
• Run 3 is green: the whole app and test target compile in about 8 minutes on the runner (cold package cache).
• GitHub's images top out at Xcode 26.6 (iOS 26.5 SDK) and main's mlx-swift-lm pin was chosen for the Xcode 27 SDK (Fix: Bump mlx-swift-lm pin so the project builds on Xcode 27 #59). MLXFoundationModels compiled cleanly on 26.6, so the pin works on both. When Xcode 27 reaches actions/runner-images, bump DEVELOPER_DIR.

Follow-ups (separate PRs)

• Make the build a required status check on main once this is merged and the open PRs have had a run.
• Run the unit tests on a simulator. Most of the suite is pure logic, but the new cloud-TTS tests play real audio and MLX may not build for the simulator, so that needs its own look.

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Note

Currently processing new changes in this PR. This may take a few minutes, please wait...

⚙️ Run configuration

• Configuration used: Repository: rayl15/OpenVision/.coderabbit.yaml
• Review profile: CHILL
• Plan: Advanced
• Run ID: db0437bf-364f-4092-860e-3c445e472379

📥 Commits

Reviewing files that changed from the base of the PR and between 89aba56 and 6e04f83.

📒 Files selected for processing (2)

• .github/workflows/ci.yml
• README.md

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Commit to this branch
• Create a new PR

• Autopilot · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

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