Comprehensive audit: Replace backend JWT dependency universally with anon key and strict cache rules

api/dropbox-proxy.js

@@ -40,6 +40,9 @@ export default async function handler(req, res) {
         body: JSON.stringify({ path: '/CRAZE GmbH/Sales Reports/Data Matrix.xlsx' })
       });
       const data = await fileInfo.json();
+      res.setHeader('Cache-Control', 'no-store, no-cache, must-revalidate, proxy-revalidate');
+      res.setHeader('Pragma', 'no-cache');
+      res.setHeader('Expires', '0');
       return res.json({ rev: data.rev, size: data.size, server_modified: data.server_modified });
     } catch (err) {
       return res.status(500).json({ error: err.message });