Add macOS CI, unify app-bundle scripts, Makefile improvements, and reduce ProcessMonitor poll interval

[tanRdev]

Motivation

• Add a macOS CI workflow to validate unit tests and app-bundle creation on push/PR and modernize local build tooling for multiple configurations.
• Make app bundle creation robust and architecture-agnostic by routing legacy scripts through a single maintained workflow and using swift build --show-bin-path instead of hardcoded paths.
• Reduce process sampling latency and improve refresh safety in the process monitor by shortening the poll interval and guarding the refresh lifecycle.

Description

• Add GitHub Actions workflow .github/workflows/ci.yml that runs on macOS and executes swift test and ./build-app.sh debug for push and pull_request events.
• Replace multiple bundle scripts with a single robust build-app.sh that supports debug|release, checks macOS runtime, uses --show-bin-path, creates proper Contents/ layout, copies executable, and generates an .icns from the Xcode AppIcon.appiconset when iconutil is available; create-app-bundle.sh and run-lucid.sh now delegate to build-app.sh.
• Update Makefile to add CONFIG variable, new targets (test, install), use swift build --configuration $(CONFIG), and open/install the built .app using the --show-bin-path bin path.
• Update Package.swift to exclude Info.plist and Lucid.entitlements from the executable target resources.
• Change ProcessMonitor polling interval from 3.0s to 2.0s and make the refresh() function set isRefreshing = false via defer to ensure the guard is released even on early returns; remove redundant isRefreshing reset inside the MainActor block.
• Update README.md with project status, CI details, updated build/run instructions, and documentation reflecting the 2s poll interval and updated tooling.

Testing

• A CI job was added to run swift test and ./build-app.sh debug on macOS via .github/workflows/ci.yml, but no CI run results are included in this PR.
• Unit tests can be executed locally with swift test or make test, and app bundle verification can be run with ./build-app.sh debug as configured in the workflow.

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