Staff shift-scheduling and rota web app

We run a business with a rotating team and we are drowning in spreadsheets when it comes to planning who works when. We want a web application dedicated to shift scheduling: a manager should be able to open a weekly grid, drag people into shifts, assign roles, and publish the finished rota to everyone in one click. This is not a customer booking system and it is not a general time clock. The single job of this tool is to plan employee shifts across the week and keep everybody informed about who is on which shift and when.

Staff members need their own view where they can set their availability and preferred days, request a swap with a colleague, or hand a shift back to the manager for reassignment. When a rota is published or changed, affected people should get a clear notification so nobody turns up on the wrong day. The manager needs guardrails: warnings for double-booking, for someone scheduled outside their stated availability, and for shifts left unassigned. On top of scheduling we want a simple hours tally so we can see planned hours per person and per week and export that for payroll, without turning the product into a full timekeeping suite.

Please propose a clean, responsive interface that works well on both desktop and phone, and a sensible data model behind it. Tell us your recommended stack, roughly how long each part will take, and where you would draw the line so the scope stays focused on scheduling.

— Weekly rota grid with drag-and-drop shift assignment and roles
— Staff availability, preferences and one-click shift-swap requests
— Notifications to staff when a rota is published or edited
— Conflict warnings for double-booking and unassigned shifts
— Planned-hours totals per person and per week with export