fix(dev): Vite-API-Proxy, Auth, Stripe-Mails und Backend-Erweiterungen

- Client: API-Basis-URL (joinApiUrl, /v1-Falle), Vite strictPort + Proxy 127.0.0.1, Nicht-JSON-Fehler

- Server: /api-404 ohne Wildcard-Bug, SPA-Fallback, Auth-Middleware, Cron, Mailer, Crypto

- Routen: OAuth-State, Email/Stripe/Analytics; client/.env.example

Made-with: Cursor

client/package-lock.json

@@ -1,11 +1,11 @@
 {
-  "name": "emailsorter-client",
+  "name": "mailflow-client",
   "version": "0.0.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
-      "name": "emailsorter-client",
+      "name": "mailflow-client",
       "version": "0.0.0",
       "dependencies": {
         "@radix-ui/react-accordion": "^1.2.12",