fix: resolve image 404 and add favicon

Markdown image src with relative paths (/images/...) now resolves to
backend API URL instead of frontend port. Added SVG favicon to eliminate
404 on /favicon.ico.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.gitignore

@@ -69,3 +69,5 @@ Desktop.ini
 *.coverage
 .coverage
 htmlcov/
+
+officefile

web/src/app/icon.svg

@@ -0,0 +1,4 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 32 32">
+  <rect width="32" height="32" rx="6" fill="#2563eb"/>
+  <text x="16" y="22" font-family="Arial,sans-serif" font-size="18" font-weight="bold" fill="white" text-anchor="middle">国</text>
+</svg>

web/src/components/chat/message-item.tsx

@@ -252,10 +252,14 @@ export default function MessageItem({ message, selectedModel }: MessageItemProps
                     td: ({ children }) => (
                       <td className="border border-border px-2 py-1.5">{children}</td>
                     ),
-                    img: ({ src, alt }: any) => (
-                      <a href={src} target="_blank" rel="noopener noreferrer" className="block my-3 group">
+                    img: ({ src, alt }: any) => {
+                      const resolvedSrc = src && src.startsWith("/")
+                        ? `${process.env.NEXT_PUBLIC_API_URL || `${window.location.protocol}//${window.location.hostname}:8000`}${src}`
+                        : src;
+                      return (
+                      <a href={resolvedSrc} target="_blank" rel="noopener noreferrer" className="block my-3 group">
                         <img
-                          src={src}
+                          src={resolvedSrc}
                           alt={alt || "图片来源"}
                           loading="lazy"
                           className="max-w-full max-h-80 rounded-lg border border-border/50 cursor-pointer
@@ -267,7 +271,7 @@ export default function MessageItem({ message, selectedModel }: MessageItemProps
                           </span>
                         )}
                       </a>
-                    ),
+                    )},
                   }}
                 >
                   {preprocessCitations(message.content, String(message.id))}