[NikitkaRa]

Summary

• The Print page (File › Print) gets paper (Letter, A4, Legal, A3) and orientation (Portrait/Landscape) pickers, as PowerPoint has; until now notes pages and handouts were always portrait US Letter. They apply to notes and handouts; full-page slides still print slide-shaped, so the pickers are disabled for that layout.
• The preview draws the chosen page shape.
• file.export (pdf), app.print and the MCP export tool accept paper: letter|a4|legal|a3 and orientation: portrait|landscape; unknown values are an error instead of a silent fallback.
• Notes pages keep the slide within the top half of the page, so landscape paper still leaves room for the notes.
• The paper table lives in deckcraft-pdf (PAPERS, paper_size) and the engine re-exports it for the UI, so the layer rules hold.

Part of ROADMAP Upcoming item 4 (Output: printing). Doesn't touch the rasterising path that #245 (vector PDF) changes.

Test plan

• cargo xtask ci (fmt, clippy, test, assets, layers, wasm)
• New deckcraft-pdf test: every paper in both orientations gives that MediaBox for notes and handouts, and every slide box stays on the page
• New engine test: pdf_options defaults to Letter portrait, takes A4 landscape and Legal, and rejects unknown paper or orientation
• Backstage test: print_params carries paper/orientation; the preview page size follows them, except for full-page slides
• MCP schema test lists paper and orientation and exports with them
• deckcraft-cli run --sample --cmd 'file.export={…"layout":"notes","paper":"a4","orientation":"landscape"}' writes MediaBox[0 0 841.89 595.28] pages
• Not checked: how the Print page looks on screen. The box can't run the app's display (libxkbcommon-x11 isn't installed)

[echelon]

Thank you for this contribution, @NikitkaRa! It has landed on main and will ship in the next DeckCraft release.

If you haven't already, please come join us on Discord: https://discord.gg/artcraft