refactor(crdt): implement proxy-resilient Yjs dual-transport sync with indexeddb offline-first and debounced sqlite persistence

Doku/reverse-proxy.md

@@ -71,8 +71,8 @@ server {
         proxy_send_timeout 3600s;
     }
 
-    # 2. Server-Sent Events Fallback (/api/v1/events)
-    location /api/v1/events {
+    # 2. Server-Sent Events Fallback (/api/v1/events & /api/v1/sync/)
+    location ~ ^/api/v1/(events|sync/) {
         proxy_pass http://127.0.0.1:8080;
         proxy_http_version 1.1;