feat: refine position roundtable workflow

frontend-web/src/core/artifacts/loader.ts

@@ -19,12 +19,32 @@ export async function loadArtifactContent({
   let enhancedFilepath = filepath;
   if (filepath.endsWith(".skill")) {
     enhancedFilepath = filepath + "/SKILL.md";
-  }
-  const url = urlOfArtifact({ filepath: enhancedFilepath, threadId, isMock, publicShareCode });
-  const response = await apiFetch(url);
-  const text = await response.text();
-  return { content: text, url };
-}
+  }
+  const url = urlOfArtifact({ filepath: enhancedFilepath, threadId, isMock, publicShareCode });
+  const response = await apiFetch(url);
+  const text = await response.text();
+  if (!response.ok) {
+    let detail = text.trim();
+    try {
+      const parsed = JSON.parse(text) as { detail?: unknown; message?: unknown };
+      const parsedDetail =
+        typeof parsed.detail === "string"
+          ? parsed.detail
+          : typeof parsed.message === "string"
+            ? parsed.message
+            : "";
+      if (parsedDetail) {
+        detail = parsedDetail;
+      }
+    } catch {
+      // Keep the raw response text as the diagnostic detail.
+    }
+    throw new Error(
+      `Failed to load artifact (${response.status})${detail ? `: ${detail}` : ""}`,
+    );
+  }
+  return { content: text, url };
+}
 
 export function loadArtifactContentFromToolCall({
   url: urlString,