chore: remove nav bar links from chatbot UI

backend/static/index.html

@@ -1048,13 +1048,7 @@
     <!-- Navigation Header -->
     <div class="nav-header">
         <h1>🧪 Canifa AI <span style="background:#fbbf24;color:#1e1e1e;padding:2px 10px;border-radius:6px;font-size:0.6em;vertical-align:middle;margin-left:8px;font-weight:700;letter-spacing:1px;">DEV EXPERIMENTAL</span></h1>
-        <div class="nav-links">
-            <a href="/static/dashboard.html">📊 Dashboard</a>
-            <a href="/static/index.html" class="active">💬 Chatbot</a>
-            <a href="/static/test_sql.html">🤖 Text-to-SQL</a>
-            <a href="/static/test_db.html">🔍 DB Test</a>
-            <a href="/static/history.html">🧾 History</a>
-        </div>
+        <div class="nav-links"></div>
     </div>
 
     <div class="main-content">