feat(bedit): add Edit Block Definition dialog and new block authoring

Open the Edit Block Definition dialog when BEDIT is invoked without an active selection, listing candidate block definitions alphabetically while filtering layout records, anonymous blocks, and external references. Allow typing a new valid block name to start an empty block editor session that only commits to the drawing block table upon explicit save.

src/ui/window/block_edit_picker.rs

@@ -0,0 +1,122 @@
+use crate::app::Message;
+use crate::scene::WireModel;
+use crate::ui::style::common::muted_style;
+use crate::ui::style::form::{hdivider, vsep};
+use iced::widget::{button, column, container, row, scrollable, text, text_input, Space};
+use iced::{Element, Fill, Length, Theme};
+
+pub(crate) struct State {
+    pub document_id: u64,
+    pub name: String,
+    pub existing_names: Vec<String>,
+    pub preview: Vec<WireModel>,
+    pub description: String,
+    pub error: Option<String>,
+}
+
+fn list_item_style(selected: bool) -> impl Fn(&Theme, button::Status) -> button::Style {
+    move |theme: &Theme, status| {
+        if selected {
+            button::primary(theme, status)
+        } else {
+            button::subtle(theme, status)
+        }
+    }
+}
+
+pub(crate) fn view(state: &State, sizing: crate::ui::modal::ModalSizing) -> Element<'_, Message> {
+    let can_apply = state.error.is_none() && !state.name.trim().is_empty();
+
+    // ── Left: Block name field and list of existing blocks ─────────────────────
+    let name_input = text_input(crate::t!("Block name").as_ref(), &state.name)
+        .on_input(Message::BlockEditPickerName)
+        .on_submit_maybe(can_apply.then_some(Message::BlockEditPickerApply))
+        .style(crate::ui::style::form::field_style);
+
+    let list_items: Vec<Element<'_, Message>> = state
+        .existing_names
+        .iter()
+        .map(|name| {
+            let is_sel = name.eq_ignore_ascii_case(state.name.trim());
+            button(text(name.clone()).size(12))
+                .on_press(Message::BlockEditPickerSelect(name.clone()))
+                .style(list_item_style(is_sel))
+                .padding([4, 8])
+                .width(Fill)
+                .into()
+        })
+        .collect();
+
+    let list_scrollable = container(scrollable(column(list_items).spacing(2)).height(Fill))
+        .style(container::bordered_box)
+        .padding(2)
+        .height(Fill);
+
+    let left_col = column![
+        text(crate::t!("Block to create or edit").into_owned()).size(12),
+        name_input,
+        list_scrollable,
+    ]
+    .spacing(8)
+    .width(Length::Fixed(240.0))
+    .height(Fill);
+
+    // ── Right: Preview and Description ─────────────────────────────────────────
+    let preview_box = column![
+        text(crate::t!("Preview").into_owned()).size(12),
+        container(super::block_palette::preview_canvas(&state.preview, 150.0))
+            .style(container::bordered_box)
+            .width(Fill)
+            .height(Length::Fixed(150.0)),
+    ]
+    .spacing(4);
+
+    let desc_text = if state.description.is_empty() {
+        crate::t!("(No description)").into_owned()
+    } else {
+        state.description.clone()
+    };
+
+    let desc_box = column![
+        text(crate::t!("Description").into_owned()).size(12),
+        container(scrollable(text(desc_text).size(11).style(muted_style)).height(Fill))
+            .style(container::bordered_box)
+            .padding(6)
+            .width(Fill)
+            .height(Fill),
+    ]
+    .spacing(4)
+    .height(Fill);
+
+    let right_col = column![preview_box, desc_box]
+        .spacing(8)
+        .width(Fill)
+        .height(Fill);
+
+    // ── Body ───────────────────────────────────────────────────────────────────
+    let body = row![left_col, vsep(sizing.height), right_col]
+        .spacing(12)
+        .height(Fill);
+
+    // ── Bottom: Error message and OK / Cancel buttons ───────────────────────────
+    let error_text = text(state.error.clone().unwrap_or_default())
+        .size(11)
+        .style(text::danger);
+
+    let buttons = row![
+        error_text,
+        Space::new().width(Fill),
+        button(text(crate::t!("OK").into_owned()))
+            .on_press_maybe(can_apply.then_some(Message::BlockEditPickerApply))
+            .style(button::primary),
+        button(text(crate::t!("Cancel").into_owned())).on_press(Message::CloseModal),
+    ]
+    .spacing(8)
+    .align_y(iced::Center);
+
+    container(column![body, hdivider(sizing.width), buttons].spacing(10))
+        .padding(16)
+        .width(sizing.width)
+        .height(sizing.height)
+        .into()
+}

src/ui/window/mod.rs

@@ -5,6 +5,7 @@ pub mod attdef_dialog;
 pub mod attribute_editor;
 pub mod auto_constrain_settings;
 pub mod block_definition;
+pub mod block_edit_picker;
 pub mod block_save_as;
 pub mod block_palette;
 pub mod browser;