feat(annotative): synthesize per-object contexts + editable UI

Make objects genuinely annotative — carrying real per-scale
representations that interoperate with other CAD apps — rather than just
a native flag. `create_annotation_context` synthesizes the extension-dict
chain (AcDbContextDataManager -> ACDB_ANNOTATIONSCALES -> per-scale leaf)
from the entity's placement; the editable Annotative toggle now covers
Text and block references as well as MText/MLeader; and a new
"Annotation Object Scale" dialog (OBJECTSCALE) adds/removes an object's
per-scale memberships. Requires the acadrust ObjectContextData encoder
(Cargo.lock bump).

Also fixes a render bug where objects carrying an *empty*
ACDB_ANNOTATIONSCALES (a single-representation marker with no per-scale
reps) were treated as annotative and (mis)scaled by the annotation factor
in scaled paper viewports, ballooning the text: an object is now
annotative-by-context only when its scale collection is non-empty, so
such objects render at their base geometry.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

src/ui/style/anno_object_scale.rs

@@ -0,0 +1,105 @@
+//! Annotation Object Scale dialog — add / remove the annotation scales a single
+//! selected object carries a per-object representation for.
+//!
+//! Each drawing scale is a row; a checkmark marks the scales the object is a
+//! member of. Clicking a row toggles membership: adding synthesizes a per-scale
+//! context (`AcDb*ObjectContextData`) at that scale, removing drops it. Shares
+//! the style / scale managers' frame so it looks consistent.
+
+use crate::app::Message;
+use crate::ui::style::style_manager::{hdivider, tb_button, BG, BORDER, DIM, LIST, TB, TEXT};
+use iced::widget::{column, container, mouse_area, row, scrollable, text, Space};
+use iced::{Background, Border, Color, Element, Fill, Theme};
+
+const MEMBER_CHECK: Color = Color {
+    r: 0.30,
+    g: 0.82,
+    b: 0.36,
+    a: 1.0,
+};
+
+/// `scales` is `(name, "paper:drawing" ratio, is_member)`. Every label is cloned
+/// into the widget tree, so the returned element borrows nothing from the args.
+pub fn view_window(
+    object_label: &str,
+    scales: &[(String, String, bool)],
+) -> Element<'static, Message> {
+    let toolbar = container(
+        row![
+            text(format!("Object: {object_label}"))
+                .size(11)
+                .color(TEXT),
+            Space::new().width(Fill),
+            tb_button("Close", Message::CloseModal, true),
+        ]
+        .spacing(4)
+        .align_y(iced::Center),
+    )
+    .style(|_: &Theme| container::Style {
+        background: Some(Background::Color(TB)),
+        ..Default::default()
+    })
+    .width(Fill)
+    .padding([5, 8]);
+
+    let rows: Vec<Element<'_, Message>> = scales
+        .iter()
+        .map(|(name, ratio, member)| {
+            let check = crate::ui::icons::check_cell(*member, MEMBER_CHECK);
+            let label = row![
+                check,
+                text(name.clone()).size(11).color(TEXT).width(Fill),
+                text(ratio.clone()).size(10).color(DIM),
+            ]
+            .spacing(4)
+            .align_y(iced::Center);
+            let cell = container(label)
+                .padding([4, 8])
+                .width(Fill)
+                .style(move |_: &Theme| container::Style {
+                    text_color: Some(TEXT),
+                    ..Default::default()
+                });
+            mouse_area(cell)
+                .on_press(Message::AnnoObjectScaleToggle(name.clone()))
+                .into()
+        })
+        .collect();
+
+    let list = container(scrollable(column(rows).spacing(1)).height(Fill))
+        .style(|_: &Theme| container::Style {
+            background: Some(Background::Color(LIST)),
+            border: Border {
+                color: BORDER,
+                width: 1.0,
+                radius: 3.0.into(),
+            },
+            ..Default::default()
+        })
+        .width(Fill)
+        .height(Fill)
+        .padding(2);
+
+    let body = container(
+        column![
+            text("Click a scale to add or remove the object's representation for it.")
+                .size(10)
+                .color(DIM),
+            list,
+        ]
+        .spacing(6)
+        .height(Fill),
+    )
+    .width(Fill)
+    .height(Fill)
+    .padding(12);
+
+    container(column![toolbar, hdivider(), body])
+        .style(|_: &Theme| container::Style {
+            background: Some(Background::Color(BG)),
+            ..Default::default()
+        })
+        .width(Fill)
+        .height(Fill)
+        .into()
+}

src/ui/style/mod.rs

@@ -7,4 +7,5 @@ pub mod tablestyle;
 pub mod point_style;
 pub mod style_list;
 pub mod scale_manager;
+pub mod anno_object_scale;
 pub mod style_manager;