Opening a .ppsx from the command line starts the slide show (#862)

docs/file-format-parity.md

@@ -18,7 +18,7 @@ PowerPoint opens and saves; Viewer = opens only).
 |---|---|---|---|---|---|
 | `.pptx` presentation | Editor | yes | yes | Broad (see below); an owned corpus of decks we author round-trips tables, charts, animations, media, sections, masters and layouts, comments, links and actions, custom shows, rotated groups, inherited placeholders, text effects and body layout, theme effects, fills, bevels, connectors, 3-D models and animation bounce end. Not measured against PowerPoint renders or decks from outside this repo | `crates/pptx/tests/corpus.rs`, `corpus_kinds.rs`, `corpus_elements.rs`, `corpus_style.rs`, `corpus_themes.rs`, `corpus_charts.rs`, `corpus_media.rs`, `roundtrip.rs`, `sample.rs`, `malformed.rs`, `sniff.rs`; opened in PowerPoint by hand 2026-10-06 |
 | `.potx` template | Editor | yes (as a presentation) | no: written with the `.pptx` content type | `file.saveTemplate` is Save As under another name | none |
-| `.ppsx` slide show | Editor | yes (as a presentation) | no: written as `.pptx` content | Doesn't start in show mode | none |
+| `.ppsx` slide show | Editor | yes (as a presentation) | no: written as `.pptx` content | Handed over by the system (command line, file association) it starts the slide show, as in PowerPoint; File › Open opens it for editing. The macOS Finder event arrives with #432 | `crates/ui-egui/src/opening.rs` tests |
 | `.pptm` / `.potm` / `.ppsm` macro-enabled | Editor | no | no | Should open and keep `vbaProject.bin` without running it | none |
 | `.ppt` / `.pot` / `.pps` 97–2003 binary | Editor | no | no | Owner decision; import only would be enough | none |
 | `.odp` OpenDocument | Editor | no | no | | none |
@@ -103,6 +103,7 @@ the round trip even though DeckCraft doesn't model it.
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-16 | trivial | A `.ppsx` opened from the command line or the file association starts the slide show (#862) |
 | 2026-10-14 | minor | Community PR wave folded: one row each for `.pptx` (seven owned corpus files), outline, 3-D models, embedded fonts, text, effects, 3-D (extrusion sides draw now), SmartArt (written as a diagram) and VBA (tags and custom XML are kept) |
 | 2026-10-12 | minor | SmartArt import lays each shape's text out on its `dsp:txXfrm` text rectangle instead of the shape box |
 | 2026-10-13 | minor | EMF/WMF rectangle clip regions limit later drawing; EMF+ records remain |