feat: enhance dashboard and canvas components with improved state management and resizing logic

- Added client mount state to the dashboard to prevent premature interactions before the component is fully loaded.
- Updated button disabling logic to ensure it reflects the component's readiness and user session state.
- Introduced zIndex handling in canvas placement context for better node layering.
- Enhanced asset and image nodes with improved resizing logic to maintain aspect ratios during adjustments.
- Refactored node components to streamline rendering and improve performance during dynamic updates.

components/canvas/canvas-placement-context.tsx

@@ -23,6 +23,7 @@ type CreateNodeWithIntersectionInput = {
   height?: number;
   data?: Record<string, unknown>;
   clientPosition?: FlowPoint;
+  zIndex?: number;
 };
 
 type CanvasPlacementContextValue = {
@@ -107,6 +108,7 @@ export function CanvasPlacementProvider({
       height,
       data,
       clientPosition,
+      zIndex,
     }: CreateNodeWithIntersectionInput) => {
       const defaults = NODE_DEFAULTS[type] ?? {
         width: 200,
@@ -140,6 +142,7 @@ export function CanvasPlacementProvider({
           ...(data ?? {}),
           canvasId,
         },
+        ...(zIndex !== undefined ? { zIndex } : {}),
       });
 
       if (!hitEdge) {