deploy: nginx liefert React-PWA-Build statt Backend-Proxy auf /

/api/ geht weiter an Uvicorn, / serviert frontend/dist mit try_files-Fallback
auf index.html (react-router-dom routet im Client).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01L85hmKbvX7Cqkq47KnQhFt

deploy/nginx_mabea.conf.template

@@ -23,11 +23,20 @@ server {
         proxy_set_header X-Forwarded-Proto $scheme;
     }
 
-    location / {
+    location /api/ {
         proxy_pass http://127.0.0.1:8000;
         proxy_set_header Host $host;
         proxy_set_header X-Real-IP $remote_addr;
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
         proxy_set_header X-Forwarded-Proto $scheme;
     }
+
+    # React-PWA (Sprint 7): statische Build-Ausgabe von frontend/dist.
+    # try_files statt 404 bei Client-Routen, da react-router-dom im Browser routet.
+    root /var/www/mabea;
+    index index.html;
+
+    location / {
+        try_files $uri $uri/ /index.html;
+    }
 }