refactor: 移除项目详情页的图片/视频显示逻辑

由于 source 字段语义不清且容易产生 CSP 错误，暂时移除
图片和视频的显示功能，待后续设计更完善的图片管理方案

src/components/project/ProjectDetail.tsx

@@ -48,48 +48,6 @@ function formatDate(date: Date | string, locale: string): string {
   }
 }
 
-// Helper function to check if URL is an image
-function isImageUrl(url: string): boolean {
-  const imageExtensions = ['.jpg', '.jpeg', '.png', '.gif', '.webp', '.svg', '.bmp']
-  const lowerUrl = url.toLowerCase()
-  return imageExtensions.some(ext => lowerUrl.includes(ext))
-}
-
-// Helper function to check if URL can be embedded in iframe
-// Many sites like GitHub, Google, etc. block iframe embedding via CSP
-function isEmbeddableUrl(url: string): boolean {
-  const hostname = new URL(url).hostname.toLowerCase()
-
-  // Whitelist of domains that allow iframe embedding
-  const embeddableDomains = [
-    'youtube.com',
-    'youtu.be',
-    'vimeo.com',
-    'player.vimeo.com',
-    'drive.google.com',
-    'docs.google.com',
-    'www.figma.com',
-    'codepen.io',
-    'jsfiddle.net',
-    'codesandbox.io',
-    'stackblitz.com',
-    'replit.com',
-    'loom.com',
-    'wistia.com',
-    'brightcove.com',
-    'dailymotion.com',
-    'twitch.tv',
-    'soundcloud.com',
-    'spotify.com',
-    'canva.com',
-    'notion.so',
-    'typeform.com',
-  ]
-
-  // Check if hostname matches any embeddable domain
-  return embeddableDomains.some((domain) => hostname === domain || hostname.endsWith('.' + domain))
-}
-
 export async function ProjectDetail({ project, locale }: ProjectDetailProps) {
   const t = await getTranslations('project')
 
@@ -149,26 +107,6 @@ export async function ProjectDetail({ project, locale }: ProjectDetailProps) {
             </span>
           ))}
         </div>
-
-        {/* Featured Image/Video Placeholder - only show if source exists */}
-        {project.source && (
-          <div className="relative w-full border-2 border-black dark:border-gray-600 bg-gray-100 dark:bg-gray-800 mb-10 overflow-hidden shadow-brutal dark:shadow-brutal-dark">
-            {isImageUrl(project.source) ? (
-              <img
-                src={project.source}
-                alt={`${displayName} demo`}
-                className="w-full h-auto"
-              />
-            ) : isEmbeddableUrl(project.source) ? (
-              <iframe
-                src={project.source}
-                className="w-full aspect-video"
-                title={`${displayName} demo`}
-                allowFullScreen
-              />
-            ) : null}
-          </div>
-        )}
       </header>
 
       {/* Article Content */}