fix(world): guard unsupported modes for external world task provider

app/api/canvas/world/tasks/route.ts

@@ -145,6 +145,26 @@ function shouldUseExternalTaskCreateApi(
   return isWorldLabsExternalTaskApi(config.baseUrl) && mode === "text";
 }
 
+function isWorldLabsModeUnsupportedByExternalProvider(
+  config: Awaited<ReturnType<typeof getWorldLabsProviderConfig>>,
+  mode: WorldTaskMode
+) {
+  return isWorldLabsExternalTaskApi(config.baseUrl) && mode !== "text";
+}
+
+function assertWorldModeSupportedByCandidate(
+  config: Awaited<ReturnType<typeof getWorldLabsProviderConfig>>,
+  mode: WorldTaskMode,
+) {
+  if (isWorldLabsModeUnsupportedByExternalProvider(config, mode)) {
+    const normalizedBaseUrl = String(config.baseUrl || "").trim() || "未知服务地址";
+    const normalizedMode = String(mode || "").trim() || "未知模式";
+    throw new Error(
+      `${normalizedBaseUrl} 的 world-generation 当前仅支持文生世界（text）。当前提交的是 ${normalizedMode}，请先切换供应商或使用文生世界。`
+    );
+  }
+}
+
 function resolveOfficialMarbleModel(model?: string | null) {
   const normalized = readOptionalTrimmedText(model);
   if (!normalized || normalized === WORLDLABS_EXTERNAL_TASK_MODEL) {
@@ -356,6 +376,7 @@ export async function POST(request: Request) {
     for (const candidate of candidates) {
       try {
         const useExternalTaskApi = shouldUseExternalTaskCreateApi(candidate, mode);
+        assertWorldModeSupportedByCandidate(candidate, mode);
         if (useExternalTaskApi) {
           const prompt = readOptionalTrimmedText(body.prompt);
           if (!prompt) {