PDF export: Add Around is clamped when a file opens, and art too large for f64 gets no effect image

document.rasterEffectsSettings accepts addAround from 0 to 1,000 pt,
but a file's raster_effects.addAround opened as it was saved. With
addAround 1e300, the area of a raster effect image overflowed f64,
the image scale became 0 and the image got the transform
[inf, NaN, NaN, inf, x, y]. PDF export left that image out, so the
drop shadow was missing.

A file's addAround now opens clamped to 0 to 1,000 pt. An effect
image whose area or scale is not finite is not made. Export then
keeps the object with its effects, and Expand Appearance expands it
without an image, as when its PNG can't be encoded.

Docs: docs/mcp.md (addAround).

crates/format/src/lib.rs

@@ -552,6 +552,7 @@ pub fn load_file(bytes: &[u8]) -> Result<NativeFile, FormatError> {
     // Untrusted: capped, named and pointing at objects the file has.
     doc.tidy_saved_selections();
     doc.tidy_graph_designs();
+    doc.raster_effects.add_around = doc.raster_effects.add_around.clamp(0.0, vectorcraft_doc::rastersettings::MAX_ADD_AROUND);
     let mut depth_notes = vec![];
     doc.limit_depth_noting(&mut depth_notes);
     let profiles = f.profiles.into_iter().filter_map(|(name, icc)| Some((name, bytes_of(&icc)?))).collect();