fix: 뉴스 리스트 — ai_summary 우선 표시 (없으면 extracted_text fallback)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/routes/news/+page.svelte

@@ -178,8 +178,9 @@
               </span>
               <div class="min-w-0 flex-1">
                 <p class="text-sm truncate {article.is_read ? 'text-[var(--text-dim)]' : 'font-medium'}">{article.title}</p>
-                {#if article.extracted_text}
-                  <p class="text-xs text-[var(--text-dim)] truncate mt-0.5">{article.extracted_text.split('\n').filter(l => l.trim() && l !== article.title)[0]?.slice(0, 120) || ''}</p>
+                {@const summary = article.ai_summary?.replace(/[*#_`~]/g, '') || article.extracted_text?.split('\n').filter(l => l.trim() && l !== article.title)[0] || ''}
+                {#if summary}
+                  <p class="text-xs text-[var(--text-dim)] truncate mt-0.5">{summary.slice(0, 120)}</p>
                 {/if}
                 <div class="flex items-center gap-2 mt-0.5 text-[10px] text-[var(--text-dim)]">
                   <span>{article.ai_sub_group || ''}</span>