feat(plugin-api): let add-ons ask for a visual style by name

Removing the binary wireframe event left add-ons with no way to set a
visual style except by spelling out a command string. Give them the
intent back, in the vocabulary everything else now speaks.

The name is carried as text rather than the render-mode type: this crate
is dependency-free by default and only pulls acadrust in behind the host
feature, which is not a weight to add to the manifest contract for one
enum. The host resolves it against the same list its ribbon, its picker
and its commands read, so an add-on can offer exactly the styles the
application does and no others. An unknown name says so and lists the
ones that exist, from that same list.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

crates/ocs_plugin_api/src/ribbon.rs

@@ -17,6 +17,15 @@ pub enum ModuleEvent {
     /// Remove all loaded models from the scene.
     #[allow(dead_code)]
     ClearModels,
+    /// Put the active viewport in a named visual style.
+    ///
+    /// The name is one of the render modes the viewport can be drawn in:
+    /// `WIREFRAME2D`, `WIREFRAME3D`, `HIDDENLINE`, `FLATSHADED`,
+    /// `GOURAUDSHADED`, `FLATSHADEDWITHEDGES`, `GOURAUDSHADEDWITHEDGES`
+    /// (case-insensitive). The host resolves it against the same list its own
+    /// ribbon and commands read, so an add-on offers exactly the styles the
+    /// application does. An unknown name is reported and nothing changes.
+    SetVisualStyle(String),
     /// Toggle the layer manager panel.
     ToggleLayers,
     /// Ask the host to open a native file picker. On selection the host

src/app/update/dialog.rs

@@ -158,6 +158,21 @@ pub(super) fn on_ribbon_tool_click(&mut self, tool_id: String, event: ModuleEven
                         self.tabs[i].properties = PropertiesPanel::empty();
                         self.command_line.push_output(crate::t!("Scene cleared.").as_ref());
                     }
+                    ModuleEvent::SetVisualStyle(name) => {
+                        use crate::modules::view::visual_style;
+                        match visual_style::mode_for_keyword(&name) {
+                            Some(mode) => return Task::done(Message::SetRenderMode(mode)),
+                            None => {
+                                // Name the styles that do exist, from the same
+                                // list every other caller reads.
+                                self.command_line.push_error(
+                                    crate::tf!("Unknown visual style \"{name}\".").as_ref(),
+                                );
+                                self.command_line
+                                    .push_info(visual_style::keyword_prompt());
+                            }
+                        }
+                    }
                     ModuleEvent::ToggleLayers => {
                         return Task::done(Message::ToggleLayers);
                     }

src/ui/ribbon/widgets.rs

@@ -1122,6 +1122,14 @@ pub fn module_event_to_message(event: ModuleEvent) -> Message {
         ModuleEvent::Command(cmd) => Message::Command(cmd),
         ModuleEvent::OpenFileDialog => Message::OpenFile,
         ModuleEvent::ClearModels => Message::ClearScene,
+        ModuleEvent::SetVisualStyle(name) => {
+            match crate::modules::view::visual_style::mode_for_keyword(&name) {
+                Some(mode) => Message::SetRenderMode(mode),
+                // Report through the command line rather than silently doing
+                // nothing, so a plugin author sees the typo.
+                None => Message::Command(format!("VISUALSTYLES {name}")),
+            }
+        }
         ModuleEvent::ToggleLayers => Message::ToggleLayers,
         // Needs the tool context + async picker — route through the normal
         // ribbon-click handler rather than a direct 1:1 message.