Pictures: WMF and EMF draw, with the metafile reader ported from WordCraft (#317)

Co-authored-by: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

xtask/src/layers.rs

@@ -47,6 +47,8 @@ pub const TABLE: &[(&str, Class)] = &[
     ("isobmff", Class::Layer(1)),
     ("media", Class::Layer(2)),
     ("color", Class::Layer(0)),
+    // WMF/EMF reader (ported from WordCraft).
+    ("metafile", Class::Layer(0)),
     ("model", Class::Layer(1)),
     ("fonts", Class::Layer(1)),
     ("text", Class::Layer(2)),