fix(jimpURL): validate Content-Type before passing to Jimp

Some servers ignore the Accept header and return unsupported formats
(e.g. image/avif). Check the actual Content-Type response header and
reject non-Jimp formats with a clear error message before decoding.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/ink-picture/utils/jimpURL.ts

@@ -1,15 +1,34 @@
-export async function loadImageFromUrl(url: string): Promise<Jimp> {
-  // 请求时指定只接受 Jimp 支持的格式
+import { Jimp } from "jimp";
+
+const SUPPORTED_MIME_TYPES = new Set([
+  "image/jpeg",
+  "image/png",
+  "image/gif",
+  "image/bmp",
+  "image/tiff",
+  "image/webp",
+]);
+
+export async function loadImageFromUrl(url: string) {
   const response = await fetch(url, {
     headers: {
-      'Accept': 'image/jpeg, image/png, image/gif, image/bmp, image/tiff, */*'
-    }
+      Accept: "image/jpeg, image/png, image/gif, image/bmp, image/tiff, image/webp, */*",
+    },
   });
 
   if (!response.ok) {
     throw new Error(`Failed to fetch: ${response.status}`);
   }
 
+  const contentType = response.headers.get("Content-Type") ?? "";
+  const mime = contentType.split(";")[0].trim().toLowerCase();
+
+  if (mime && !SUPPORTED_MIME_TYPES.has(mime)) {
+    throw new Error(
+      `Unsupported image format: ${mime}. Supported: ${[...SUPPORTED_MIME_TYPES].join(", ")}`,
+    );
+  }
+
   const arrayBuffer = await response.arrayBuffer();
   const buffer = Buffer.from(arrayBuffer);