Fix canvas transfer timeouts and move images out of snapshots

src/lib/canvas-v2.ts

@@ -82,10 +82,10 @@ export function decodeNodeExtensions(data: Record<string, unknown>, schema: numb
   }
   return extensions;
 }
-export function managedImageSource(src?: string) {
+export function managedImageSource(src?: string, preview = false) {
   if (!src) return src;
   try { const url = new URL(src); const match = url.pathname.match(/^\/projects\/endoleap\/(workspaces\/[A-Za-z0-9_-]+\/assets\/[A-Za-z0-9_-]+)$/);
-    if (url.origin === "https://api.foundry.entroia.com" && match) return "/api/foundry/" + match[1];
+    if (url.origin === "https://api.foundry.entroia.com" && match) return "/api/foundry/" + match[1] + (preview ? "?variant=preview" : "");
   } catch { /* inline and demo images are already browser-readable */ }
   return src;
 }