Art museum exhibition planning and gallery wall layout tool

Build Atelier Atlas, an exhibition planning workspace for an independent contemporary art museum. Seed 18 fictional artworks with original locally rendered geometric illustrations, dimensions, medium, artist, loan availability dates and handling notes. Provide an editorial collection browser with filters, an artwork detail drawer and an exhibition shortlist. The central feature is a scaled two-dimensional gallery wall planner for three rooms: place shortlisted artworks on named walls, edit placement with keyboard-operable controls and show width usage and overlap/out-of-bounds warnings. Do not require drag-and-drop as the only input. Add a loan calendar that flags unavailable works for the chosen exhibition date range and a packing checklist generated from the selected artworks. Users can save a named exhibition, reopen it and export its artwork/placement manifest as JSON. Design it like a gallery catalogue, with generous whitespace, serif headings and restrained burgundy accents; the art and spatial plan should dominate. Deliver a self-contained demo with synthetic data clearly labelled, English product copy, and no external APIs, credentials or remote assets. Use HTML/CSS/JavaScript with a directly previewable root index.html. Provide distinct, polished visual design, accessible labelled controls, visible keyboard focus and useful empty/error states. Persist user edits locally with a reset-demo action. Include a short README and executable Node built-in tests for the important domain calculations. Verify the actual main user journey in a browser at mobile and desktop widths before delivery. An artwork is available only when its inclusive loan-availability interval contains the entire exhibition interval. Reject an exhibition end before its start. Before delivery, exercise each acceptance criterion with recorded, observable results. For persistence, save a distinctive value, reload the actual page and observe the restored UI. Keep domain calculations separate enough for tests to import the production functions.

Improve and deliver the existing Atelier Atlas exhibition planner by correcting placement identity. Currently adding the same artwork to two walls creates two placements, but move actions find only the first artwork id and can move an artwork on a hidden wall. Use the complete placement identity consistently for move, edit and remove actions so an operation on the selected wall affects only that placement. Preserve existing exhibition, loan-date, persistence and export features. Add a regression through the production placement code using Quiet Meridian on North Gallery's Long wall and Window wall, both initially x=20. Move the Window wall placement left twice: the Long wall placement must remain x=20, while the Window wall placement moves and its own out-of-bounds warning is shown if x becomes negative. Verify this through real browser controls, save and actually reload the exhibition, and confirm both placements remain correct. Run domain tests and gather evidence for all six original acceptance criteria together after the final modification.