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/ui/window/mod.rs

@@ -1,4 +1,5 @@
 pub mod about;
+pub mod attdef_dialog;
 pub mod block_definition;
 pub mod block_palette;
 pub mod browser;