feat: add image proxy route and integrate it into media handling for improved Twitter content fetching

apps/frontend/src/app/add/page.tsx

@@ -4,6 +4,7 @@ import { FormEvent, useEffect, useMemo, useRef, useState } from "react";
 import Link from "next/link";
 import { useRouter } from "next/navigation";
 import Header from "../../components/header";
+import { proxyMediaUrl } from "../../lib/media";
 
 type SourceType = "twitter" | "pixiv" | "direct";
 
@@ -194,7 +195,7 @@ export default function AddPage() {
                 const mediaItems = data.tweet?.media?.all || data.tweet?.media?.photos || [];
                 const items: PreviewItem[] = mediaItems
                     .map((m) => ({
-                        url: (m as any).thumbnail_url || (m as any).url || "",
+                        url: proxyMediaUrl((m as any).thumbnail_url || (m as any).url || ""),
                         type: (((m as any).type === "video" || (m as any).type === "gif" || ((m as any).format && (m as any).format.includes("video"))) ? "video" : "image") as "image" | "video"
                     }))
                     .filter((item) => item.url.length > 0);

apps/frontend/src/lib/media.ts

@@ -0,0 +1,25 @@
+/**
+ * pbs.twimg.com 등 트위터 미디어 URL을 백엔드 프록시 경로로 변환합니다.
+ * 트래킹 보호나 방화벽으로 인해 직접 접근이 막힐 수 있기 때문입니다.
+ */
+const PROXIED_HOSTS = [
+  "pbs.twimg.com",
+  "video.twimg.com",
+  "ton.twimg.com",
+  "abs.twimg.com",
+];
+
+export function proxyMediaUrl(url: string | undefined | null): string {
+  if (!url) return "";
+
+  try {
+    const parsed = new URL(url);
+    if (PROXIED_HOSTS.includes(parsed.hostname)) {
+      return `/api/proxy/image?url=${encodeURIComponent(url)}`;
+    }
+  } catch {
+    // 유효하지 않은 URL이면 그대로 반환
+  }
+
+  return url;
+}