fix: also remove New Session tab from JS render function

The renderSessionTabs() function was re-adding the + button. Now it only
renders session tabs without the new session button. Users can still
create sessions via Ctrl+N keyboard shortcut.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/web/public/app.js

@@ -506,13 +506,6 @@ class ClaudemanApp {
       `;
     }
 
-    // Add the "+" button at the end of session tabs
-    html += `
-      <div class="session-tab new-tab" onclick="app.createNewSession()" title="New Session (Ctrl+N)">
-        <span>+</span>
-      </div>
-    `;
-
     container.innerHTML = html;
   }