feat: add NodePalette and PipelineCanvas components for enhanced flow node management

- Introduced NodePalette component to display draggable nodes categorized by type.
- Implemented PipelineCanvas component to manage the flow of nodes and connections.
- Integrated drag-and-drop functionality for adding nodes to the canvas.
- Created a catalog of node types with associated metadata for rendering in the palette.
- Established conversion functions between pipeline definitions and React Flow state.
- Added inspector for editing node properties and managing connections.
- Updated Next.js configuration for production and development environments.
- Removed obsolete embed.go file and added nginx configuration for serving the app.
- Updated package dependencies including @xyflow/react for enhanced functionality.
- Added TypeScript definitions for CSS imports to support styling in components.

web/app/executions/view/page.tsx

@@ -105,7 +105,7 @@ function ExecutionView() {
   const terminal = ["success", "completed", "failed", "error"].includes(s.toLowerCase());
 
   return (
-    <div className="space-y-6">
+    <div className="space-y-6 p-6">
       <div className="flex items-center justify-end gap-2">
         <Button
           variant="outline"