feat(rust-frontend): remove unused api_client parameter and update result type

- Updated main function return type from eframe::Result to eframe::Result<()>
- Removed unused std::sync::Arc import in main.rs
- Marked unused api_client parameters as _api_client in node_editor.rs and preview_pane.rs
- Added underscore prefix to unused image_data variable in preview_pane.rs
- Improves code clarity by removing unused dependencies and parameters

rust-frontend/src/main.rs

@@ -1,5 +1,4 @@
 use eframe::egui;
-use std::sync::Arc;
 
 mod node_editor;
 mod node_panel;
@@ -53,7 +52,7 @@ impl eframe::App for ComfyUIApp {
     }
 }
 
-fn main() -> eframe::Result {
+fn main() -> eframe::Result<()> {
     let native_options = eframe::NativeOptions {
         viewport: egui::ViewportBuilder::default()
             .with_title("ComfyUI Rust Frontend")

rust-frontend/src/node_editor.rs

@@ -36,7 +36,7 @@ impl NodeEditor {
         }
     }
 
-    pub fn ui(&mut self, ui: &mut egui::Ui, api_client: &ApiClient) {
+    pub fn ui(&mut self, ui: &mut egui::Ui, _api_client: &ApiClient) {
         ui.heading("Node Editor");
         
         // Create a scroll area for the node editor

rust-frontend/src/preview_pane.rs

@@ -14,7 +14,7 @@ impl PreviewPane {
         }
     }
 
-    pub fn ui(&mut self, ui: &mut egui::Ui, api_client: &ApiClient) {
+    pub fn ui(&mut self, ui: &mut egui::Ui, _api_client: &ApiClient) {
         ui.set_min_width(300.0);
         ui.heading("Preview Pane");
         
@@ -23,7 +23,7 @@ impl PreviewPane {
         // Display current preview info
         ui.label(format!("Image: {}", self.image_name));
         
-        if let Some(data) = &self.image_data {
+        if let Some(_data) = &self.image_data {
             // Try to display the image (simplified)
             ui.label("Image would be displayed here");