Part of #637: area type, threaded type and type on a path from the text document

Illustrator EPS and .ai type is made whole from the file's text
document, shown or hidden: point type, area type (a story in several
frames as threaded type that flows when the file opens) and type on a
path, with its fonts, size, leading, tracking, scaling, baseline shift,
fill and stroke colours (grey, RGB or CMYK), alignment, indents and
paragraph spacing. The page's drawing of that type, often in pieces, is
left out; where the text document can't say, type that shows still
comes from the page.

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

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

@@ -228,6 +228,10 @@ pub fn load_with(name: &str, bytes: &[u8], opts: &LoadOptions) -> Result<Loaded>
         _ if format.raster => (raster_doc(&title, bytes)?, vec![], false),
         _ => return Err(err(format!("{} files can't be opened yet", format.label))),
     };
+    // Threaded type read from a file flows through its frames.
+    if !doc.text_threads.is_empty() && !restored {
+        crate::cmd::threads::reflow(&Document::new(1.0, 1.0), &mut doc);
+    }
     if let Some(mode) = opts.color_mode.filter(|m| *m != doc.color_mode) {
         super::super::colormgmt::set_color_mode(&mut doc, mode, true, None, opts.grays);
     }