M4.55: File Info with author, description, keyword chips, rating and copyright, written to SVG, PDF and PNG

file.info takes and reports the title, author, author title, description,
keywords, rating, copyright status, notice and URL in one undo step, plus
the read-only created (file.new) and modified (every save to a file) dates;
junk values are refused. Document.metadata (DocMetadata) round-trips
natively. PDF export writes author, subject and keywords to the info
dictionary and XMP, PNG export writes tEXt/iTXt chunks, SVG export writes
<desc> and, with the metadata option, every field as Dublin Core. The File
Info dialog (fileInfo, ui.fileInfoDialog) edits it with keyword chips and
star ratings.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/engine/src/cmd/fileio/encode.rs

@@ -272,7 +272,14 @@ pub fn encode_all(doc: &Document, format: &str, p: &Value) -> Result<Encoded> {
                 let region = doc.artboards.get(b).ok_or_else(|| bad(C, format!("no artboard {}", b + 1)))?.rect;
                 check_format_size(f, region.width() * scale, region.height() * scale)?;
                 vectorcraft_render::raster_size(region, scale).map_err(|e| bad(C, e))?;
-                enc.files.push((Some(b), renderer.export_region(doc, region, format, &settings).map_err(EngineError::Other)?));
+                let bytes = renderer.export_region(doc, region, format, &settings).map_err(EngineError::Other)?;
+                // File Info as PNG text chunks.
+                let bytes = if format == RasterFormat::Png {
+                    vectorcraft_render::encode::png::with_text(bytes, &doc.metadata.png_text(&doc.title))
+                } else {
+                    bytes
+                };
+                enc.files.push((Some(b), bytes));
             }
             if enc.files.is_empty() {
                 return Err(bad(C, "the document has no artboard"));