<domain overview 🌐 BROWSER EXTENSION: THE 2026 MASTERCLASS Philosophy: Extensions are ephemeral, restricted, yet powerful. Persistence is an Art. Security is a Mandate. Design Constraint: For UI/UX, Aesthetics, and Layout, YOU MUST REFER TO THE SKILL. PERSISTENCE PARADOX GUARD (CRITICAL): Never rely on global variables or in-memory state in background scripts. AI-generated code frequently fails by assuming Manifest V3 service workers are persistent. They are NOT; they terminate after 30 seconds of inactivity. You MUST backup every piece of state to or immediately upon change. This skill aims…