lecturn-deck

Convert PowerPoint (.pptx) ⇄ the lecturn.deck/1 JSON slide schema, and author/validate that JSON, with a bundled normative spec and a stdlib-only Python two-way converter. Import a .pptx into an editable presentation → slides → positioned-element tree (a discriminated union: text, stat, chart, image, line, shape, table, group, widget, embed) over a fixed canvas — media extracted, inherited placeholder geometry resolved, every construct classified F0 native / F1 carried / F2 fallback / F3 flagged with no silent loss — or build a structurally valid .pptx back from a deck JSON (native tables/charts, embedded media, notes, verbatim re-emission of carried parts; native-only stat/widget/embed exported as an honest static projection). The XML parser is hardened for untrusted uploads (refuses DTD/entity for XXE/billion-laughs, caps decompression for zip bombs) without any third-party dependency. Bundles the full schema + PPTX crosswalk spec, a worked example deck, a specialist agent for convert-validate-verify loops, and the deckconv CLI (from-pptx / to-pptx / validate / inspect).