[cmpadden]

Summary

• Add a small Swift/AppKit helper for centered, click-through glass toasts that do not steal focus or create Notification Center history.
• Use native NSGlassEffectView on macOS 26+, with a visual-effect HUD fallback on macOS 13–25, built-in SF Symbols, and a two-second dismissal.
• Route caffeine toggles and startup/reload feedback through a shared Lua wrapper; keep existing canvas alerts as fallback and leave window-manager alerts unchanged.
• Add explicit build/preview targets, ignore generated executables, and document setup and rollback.