refactor(styles): replace cycle buttons with dropdowns

The enum/handle pickers in the MLeader, Table and Dimension style
editors used "Cycle" buttons, which were awkward. Replace them with
pick_list dropdowns:
- MLeader: path type, content type, text angle, text alignment.
- Table per-cell: alignment (9 anchors).
- Dimension: arrowhead blocks (DIMBLK/1/2/LDRBLK) and ext-line linetypes
  (DIMLTYPE/LTEX1/LTEX2), options resolved from block_records/line_types.

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

src/ui/dimstyle.rs

@@ -1,7 +1,9 @@
 //! Dimension Style Manager window — fills the entire OS window.
 
 use crate::app::{DsField, Message};
-use iced::widget::{button, checkbox, column, container, row, scrollable, text, text_input, Space};
+use iced::widget::{
+    button, checkbox, column, container, pick_list, row, scrollable, text, text_input, Space,
+};
 use iced::{Background, Border, Color, Element, Fill, Theme};
 
 const TB: Color = Color {
@@ -130,7 +132,7 @@ pub struct DimStyleValues<'a> {
     pub dimalttz: &'a str,
     pub dimtolj: &'a str,
     pub dimtzin: &'a str,
-    // Resolved display names for the block/linetype Handle fields.
+    // Resolved selected names for the block/linetype Handle fields.
     pub dimblk_name: String,
     pub dimblk1_name: String,
     pub dimblk2_name: String,
@@ -138,6 +140,9 @@ pub struct DimStyleValues<'a> {
     pub dimltex_name: String,
     pub dimltex1_name: String,
     pub dimltex2_name: String,
+    // Dropdown option lists shared by the arrowhead / linetype fields.
+    pub block_opts: Vec<String>,
+    pub lt_opts: Vec<String>,
 }
 
 fn btn_s(accent: bool) -> impl Fn(&Theme, button::Status) -> button::Style {
@@ -384,16 +389,20 @@ pub fn view_window<'a>(
             .into()
     };
 
-    // Block / linetype Handle cycler: shows the resolved name and a button that
-    // advances to the next available block-record (arrowheads) or linetype.
-    let hrow = move |label: &'static str, name: String, field: &'static str| -> Element<'a, Message> {
+    // Block / linetype Handle dropdown: pick a block-record (arrowheads) or a
+    // linetype by name from the available records.
+    let hrow = move |label: &'static str,
+                     options: Vec<String>,
+                     selected: String,
+                     field: &'static str|
+          -> Element<'a, Message> {
         row![
             lbl(label),
-            text(name).size(11).width(110),
-            button(text("Cycle").size(10))
-                .on_press(Message::DsCycleHandle(field))
-                .style(btn_s(false))
-                .padding([2, 8]),
+            pick_list(options, Some(selected), move |value| {
+                Message::DsSetHandle { field, value }
+            })
+            .text_size(11)
+            .width(150),
         ]
         .spacing(8)
         .align_y(iced::Center)
@@ -444,18 +453,18 @@ pub fn view_window<'a>(
             row![lbl("Ext line weight (DIMLWE)"), mk_field(DsField::Dimlwe, vals.dimlwe)].spacing(8).align_y(iced::Center),
             chk("Fixed-length ext lines (DIMFXLON)", vals.dimfxlon, DsField::Dimfxlon),
             row![lbl("Fixed length (DIMFXL)"), mk_field(DsField::Dimfxl, vals.dimfxl)].spacing(8).align_y(iced::Center),
-            hrow("Dim line linetype (DIMLTYPE)", vals.dimltex_name.clone(), "dimltex_handle"),
-            hrow("Ext line 1 linetype (DIMLTEX1)", vals.dimltex1_name.clone(), "dimltex1_handle"),
-            hrow("Ext line 2 linetype (DIMLTEX2)", vals.dimltex2_name.clone(), "dimltex2_handle"),
+            hrow("Dim line linetype (DIMLTYPE)", vals.lt_opts.clone(), vals.dimltex_name.clone(), "dimltex_handle"),
+            hrow("Ext line 1 linetype (DIMLTEX1)", vals.lt_opts.clone(), vals.dimltex1_name.clone(), "dimltex1_handle"),
+            hrow("Ext line 2 linetype (DIMLTEX2)", vals.lt_opts.clone(), vals.dimltex2_name.clone(), "dimltex2_handle"),
         ]
         .spacing(7)
         .into(),
         1 => column![
             text("Arrows").size(11).color(ACCENT),
-            hrow("Arrowhead (DIMBLK)", vals.dimblk_name.clone(), "dimblk"),
-            hrow("1st arrowhead (DIMBLK1)", vals.dimblk1_name.clone(), "dimblk1"),
-            hrow("2nd arrowhead (DIMBLK2)", vals.dimblk2_name.clone(), "dimblk2"),
-            hrow("Leader arrowhead (DIMLDRBLK)", vals.dimldrblk_name.clone(), "dimldrblk"),
+            hrow("Arrowhead (DIMBLK)", vals.block_opts.clone(), vals.dimblk_name.clone(), "dimblk"),
+            hrow("1st arrowhead (DIMBLK1)", vals.block_opts.clone(), vals.dimblk1_name.clone(), "dimblk1"),
+            hrow("2nd arrowhead (DIMBLK2)", vals.block_opts.clone(), vals.dimblk2_name.clone(), "dimblk2"),
+            hrow("Leader arrowhead (DIMLDRBLK)", vals.block_opts.clone(), vals.dimldrblk_name.clone(), "dimldrblk"),
             row![
                 lbl("Arrow size (DIMASZ)"),
                 mk_field(DsField::Dimasz, vals.dimasz)