ATTDEF: dialog, -ATTDEF prompts, tag display, Properties and ribbon

Attribute Definition dialog and Edit Attribute Definition dialog, -ATTDEF
with the reference prompts and modes (AFLAGS), tag shown in the drawing,
justification-aware grips, reworked Properties with validation, Home Block
slide-out and Insert Block Definition panel, and the codec patch for
ATTDEF DXF output and the R2013+ solid wire cache.

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

src/app/commands/mod.rs

@@ -4,6 +4,7 @@ use crate::scene::Scene;
 use iced::Task;
 use std::path::PathBuf;
 
+mod attdef;
 mod blocks;
 mod xref_attach;
 mod dim;
@@ -278,6 +279,9 @@ impl OpenCADStudio {
         if let Some(t) = self.dispatch_pc_extract(cmd, i) {
             return Some(t);
         }
+        if let Some(t) = self.dispatch_attdef(cmd, i) {
+            return Some(t);
+        }
         if let Some(t) = self.dispatch_draw(cmd, i) {
             return Some(t);
         }