fix: update admin token check logic and improve comments for clarity

feat: add condition to only delete manually added stocks from DB
docs: clarify stock notes saving method and Alpaca mode indicator fetching
chore: update binary database file

app/lib/auth.server.ts

@@ -1,6 +1,8 @@
 export async function requireAdmin(request: Request) {
-  // Simple fallback: check x-admin-token header vs ADMIN_TOKEN
+  // If ADMIN_TOKEN is not set, allow access (dev mode)
+  if (!process.env.ADMIN_TOKEN) return;
+  // Otherwise check the x-admin-token header
   const token = request.headers.get('x-admin-token');
-  if (process.env.ADMIN_TOKEN && token === process.env.ADMIN_TOKEN) return;
+  if (token === process.env.ADMIN_TOKEN) return;
   throw new Response('Unauthorized', { status: 401 });
 }