fix: 메인 헤더 로고 284x284 원본 크기로 표시

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/static/styles.css

@@ -16,7 +16,7 @@
   --muted:         #627590;
   --success:       #127a46;
   --danger:        #b91c1c;
-  --header-h:      44px;
+  --header-h:      284px;
 }
 
 /* ── 리셋 & 기본 ─────────────────────────────────── */
@@ -337,8 +337,8 @@ a { color: inherit; text-decoration: none; }
 .header-logo-mark svg { color: #fff; }
 
 .header-logo-img {
-  height: 48px;
-  width: auto;
+  width: 284px;
+  height: 284px;
   object-fit: contain;
   flex-shrink: 0;
 }

app/templates/main.html

@@ -11,7 +11,8 @@
     <!-- ── 헤더 ── -->
     <header class="header">
       <div class="header-brand">
-        <span class="header-brand-title">DBX 업무포털</span>
+        <img src="/static/dbx-logo.png" alt="DBX Corporation" class="header-logo-img" />
+        <span class="header-portal">업무 포털</span>
       </div>
 
       <div class="header-user">