fix: 사이드바 트리에서 News 제외 + 뉴스 페이지 ☰ 숨김

- tree API: ai_domain != 'News' 필터
- +layout: /news 경로에서 사이드바 토글 버튼 숨김
- DB: 뉴스 ai_sub_group을 신문사명으로 재설정

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

app/api/documents.py

@@ -103,7 +103,7 @@ async def get_document_tree(
         sql_text("""
             SELECT ai_domain, COUNT(*)
             FROM documents
-            WHERE ai_domain IS NOT NULL AND ai_domain != ''
+            WHERE ai_domain IS NOT NULL AND ai_domain != '' AND ai_domain != 'News'
               AND deleted_at IS NULL
             GROUP BY ai_domain
             ORDER BY ai_domain

frontend/src/routes/+layout.svelte

@@ -62,6 +62,7 @@
       <!-- 상단 nav -->
       <nav class="flex items-center justify-between px-4 py-2 border-b border-[var(--border)] bg-[var(--surface)] shrink-0">
         <div class="flex items-center gap-3">
+          {#if !$page.url.pathname.startsWith('/news')}
           <button
             onclick={() => sidebarOpen = !sidebarOpen}
             class="p-1.5 rounded-md hover:bg-[var(--border)] text-[var(--text-dim)]"
@@ -71,6 +72,7 @@
               <path d="M3 12h18M3 6h18M3 18h18"/>
             </svg>
           </button>
+          {/if}
           <a href="/" class="text-sm font-semibold hover:text-[var(--accent)]">PKM</a>
           <span class="text-[var(--text-dim)] text-xs">/</span>
           <a href="/documents" class="text-xs hover:text-[var(--accent)]">문서</a>