Insert Reference panel: one Attach, labelled underlay tools, slide-out with Edit Reference and xref fading

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

src/app/commands/mod.rs

@@ -610,12 +610,15 @@ inventory::submit!(crate::command::CommandRegistration {
         "FRAME",
         "IMAGEFRAME",
         "PDFFRAME",
+        "XDWGFADECTL",
         "POINTCLOUDCLIPFRAME",
         "XCLIPFRAME",
         "WIPEOUTFRAME",
         "FRAMES0",
         "FRAMES1",
         "FRAMES2",
+        "UOSNAP0",
+        "UOSNAP1",
         "HALOGAP",
         "TRACEWID",
         "SKETCHINC",