feat(layers): search boxes in the layer dropdown and Layer Manager (#343)

The ribbon layer dropdown gets a live search field above the list
(cleared when the dropdown closes, panel height tracks the filtered
count), and the Layer Manager toolbar gets one too. Both filter by
case-insensitive substring while toggle/rename messages keep the
original row indices, so acting on a filtered row hits the right layer.

Co-Authored-By: Claude Fable 5 <[email protected]>

src/app/command_driver.rs

@@ -1578,7 +1578,7 @@ impl OpenCADStudio {
                             // window — the same points the grips expose — then
                             // refresh the stored measurement so the value tracks
                             // the stretched geometry.
-                            let mut mv = |p: &mut acadrust::types::Vector3| {
+                            let mv = |p: &mut acadrust::types::Vector3| {
                                 if in_win(p.x, p.y) {
                                     p.x += dx;
                                     p.y += dy;

src/app/mod.rs

@@ -1625,6 +1625,10 @@ pub enum Message {
     // ── Ribbon ────────────────────────────────────────────────────────────
     /// User selected a layer from the layer combobox in the ribbon.
     RibbonLayerChanged(String),
+    /// Live text of the ribbon layer dropdown's search box (#343).
+    RibbonLayerFilterChanged(String),
+    /// Live text of the Layer Manager's search box (#343).
+    LayerManagerFilterChanged(String),
     /// User changed the active color in the Properties toolbar.
     RibbonColorChanged(AcadColor),
     /// Toggle the full ACI palette inside the ribbon color picker.

src/app/update/mod.rs

@@ -3246,6 +3246,15 @@ impl OpenCADStudio {
                 self.modal_drag_last = None;
                 Task::none()
             }
+            Message::RibbonLayerFilterChanged(f) => {
+                self.ribbon.layer_filter = f;
+                Task::none()
+            }
+            Message::LayerManagerFilterChanged(f) => {
+                let i = self.active_tab;
+                self.tabs[i].layers.filter = f;
+                Task::none()
+            }
             Message::LayerNameColGrab => {
                 // Start a Name-column divider drag; rides ModalDragMove.
                 self.layer_col_dragging = true;