I have a working single-user HTML/CSS/JavaScript application that currently saves everything to LocalStorage. The front-end, calculations, and overall workflow should remain essentially unchanged; what I need is a solid Google Cloud back-end that turns this into a secure, multi-user, online product. Scope of work • Migrate the existing LocalStorage schema to a managed database on Google Cloud—Firestore or another service you recommend—while keeping the data structure intact. • Implement email-and-password authentication, complete with session handling and password-reset flow. • Add multi-tenant logic so each signed-in user sees only their own records (plus any shared reference data). • Enable real-time or near real-time syncing so edits made by one user become visible to others within seconds. • Host the static front-end on the Google Cloud option that best fits your architecture (Cloud Storage, Cloud Run, App Engine, etc.). • Supply a migration tool or script to import existing LocalStorage data into the new cloud database. Acceptance criteria • Reliable login, logout, and password-reset functionality. • Cross-user updates visible in ≤5 seconds without manual refresh. • All calculations deliver identical results to the current offline version. • Complete source code in a Git repo plus a README covering environment variables and deployment steps. • Brief hand-off call or video walkthrough on completion. Put together a detailed project proposal that explains your chosen Google Cloud services, security model, and milestone breakdown; this proposal will be the main factor in my selection. Links to past, similar work are welcome, but the clarity of your plan matters most.