refactor(chat): tighten media cache boundaries

src/app/chat/components/image-bubble.tsx

@@ -13,8 +13,12 @@ import { useRouter } from "next/navigation";
 import { useState } from "react";
 
 import { ROUTE_BUILDERS } from "@/router/routes";
+import {
+  isBrowserLocalChatImageSource,
+  normalizeChatImageSource,
+} from "@/lib/chat/chat_media_url";
+import { useCachedChatMediaUrl } from "@/lib/chat/use_cached_chat_media_url";
 
-import { useCachedChatMediaUrl } from "../hooks/use-cached-chat-media-url";
 import styles from "./image-bubble.module.css";
 
 export interface ImageBubbleProps {
@@ -36,9 +40,9 @@ export function ImageBubble({
     kind: "image",
   });
 
-  const src = decodeBase64Image(mediaUrl || imageUrl);
+  const src = normalizeChatImageSource(mediaUrl || imageUrl);
   const canOpen = Boolean(messageId);
-  const shouldUseNativeImage = isBrowserLocalImageSrc(src);
+  const shouldUseNativeImage = isBrowserLocalChatImageSource(src);
 
   const openImage = () => {
     if (!messageId) return;
@@ -85,17 +89,3 @@ export function ImageBubble({
     </div>
   );
 }
-
-/** 解析 base64 data URI（`data:image/png;base64,...`），否则原样返回 */
-function decodeBase64Image(uri: string): string {
-  // 已是 data URI 或 http(s) URL：直接返回
-  if (uri.startsWith("data:") || uri.startsWith("http")) {
-    return uri;
-  }
-  // 裸 base64 字符串 → 包装成 data URI（PNG 兜底）
-  return `data:image/png;base64,${uri}`;
-}
-
-function isBrowserLocalImageSrc(src: string): boolean {
-  return src.startsWith("blob:") || src.startsWith("data:");
-}