As a program manager I want a grid/map view of the program schedule for QA before publishing

Kompassi V1 had a literal grid/map view of the program schedule (rooms × time slots) that program managers used to preview the schedule before publishing. V2 does not have an equivalent.

## Use cases

- **Quality control before publishing**: Visually inspect the schedule for errors (wrong room, wrong time, overlaps) before it goes live
- **Verify all approved programs are scheduled**

## Requested behaviour

A read-only grid view of the program schedule, accessible to program managers, showing:
- Rooms as columns
- Time as rows
- Program blocks as cells, linking to the program item for easy correction

This view does not need to support drag-and-drop scheduling — a static view is sufficient.

## Background

Reported by Desucon Frostbite 2026 program management, who noted that in V1 this view prevented many scheduling errors from reaching the public.