Replace all clauseguard.com URLs with clauseguardweb.netlify.app

Website↔Extension bridge: auto-detect login, sync user/plan to extension, guest mode, scan history, user bar in popup

UI overhaul: Lucide icons (no emojis), expandable clause cards, severity filters, progress bars, copy/PDF actions, shared nav, interactive hover states

🛡️ ClauseGuard v1.0 — Full codebase: Extension + Website + API + ML