feat: support absolute path as image src

frontend/src/core/artifacts/utils.ts

@@ -16,3 +16,7 @@ export function urlOfArtifact({
 export function extractArtifactsFromThread(thread: AgentThread) {
   return thread.values.artifacts ?? [];
 }
+
+export function resolveArtifactURL(absolutePath: string, threadId: string) {
+  return `${getBackendBaseURL()}/api/threads/${threadId}/artifacts${absolutePath}`;
+}