feat: enhance AI image generation and prompt handling in canvas components

- Introduced shimmer animation for loading states in AI image nodes.
- Updated prompt node to handle image generation with improved error handling and user feedback.
- Refactored AI image node to manage generation status and display loading indicators.
- Enhanced data handling in canvas components to include canvasId for better context management.
- Improved status message handling in Convex mutations for clearer user feedback.

app/globals.css

@@ -127,4 +127,19 @@
   html {
     @apply font-sans;
   }
+}
+
+@keyframes shimmer {
+  0% {
+    transform: translateX(-100%);
+  }
+  100% {
+    transform: translateX(100%);
+  }
+}
+
+@layer utilities {
+  .animate-shimmer {
+    animation: shimmer 1.5s ease-in-out infinite;
+  }
 }