feat(annotative): scale text/dims/tables/blocks at the annotation scale + editable property pickers

Render: annotative-ness is resolved centrally in scene::annotative::is_annotative
(per-object context dictionary, legacy XDATA, or annotative style) so the bake and
the properties panel agree. Text, dimensions, tables and blocks now display at the
current annotation scale in model space. An annotative block scales as one uniform
unit about its insertion point — its internal geometry and attributes are carried by
that scale instead of being scaled individually, fixing the block-attribute size
regression. Tables scale their column/row/margin geometry.

Properties: the handle- and flag-backed rows are now editable pickers — MLEADER
multileader style / text style / arrowhead / leader linetype, General Material, and
Plot style (named plot-style mode only; the color-dependent mode stays read-only,
which is correct). A picked name is resolved back to its handle in the update loop,
where the document is in scope. Annotative Yes/No and the annotation-scale row are
shown per object.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/scene/mod.rs

@@ -5,6 +5,7 @@
 //   pick    — hit-testing, selection, grips, spatial index, xclip
 //   view    — camera, transforms, viewport, render pipeline driver
 //   cache   — block-definition and property caches
+pub mod annotative;
 pub mod cache;
 pub mod convert;
 pub mod model;
@@ -1158,12 +1159,12 @@ impl Scene {
         } else {
             self.paper_bg_color
         };
-        let anno = if self.current_layout == "Model" {
-            self.annotation_scale
-        } else {
-            1.0
-        };
-        let built = cache::block_cache::BlockCache::build(&self.document, anno, bg);
+        // Block definitions are cached at block-local size (annotation scale
+        // 1.0). An annotative block scales as ONE unit at the INSERT level, so
+        // its internal geometry / text / attributes must NOT be scaled
+        // individually (that would double-scale — AutoCAD even forbids
+        // annotative attributes inside annotative blocks for this reason).
+        let built = cache::block_cache::BlockCache::build(&self.document, 1.0, bg);
         let arc = Arc::new(built);
         *self.block_defn_cache.borrow_mut() = Some((self.block_epoch, Arc::clone(&arc)));
         arc