fix: add nginx SPA fallback to resolve deck 404 on direct URL access

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.gitea/workflows/deploy.yaml

@@ -37,4 +37,6 @@ jobs:
             --restart unless-stopped \
             -p 8080:80 \
             nginx:alpine
+          docker cp nginx.conf slides-nginx:/etc/nginx/conf.d/default.conf
           docker cp dist/. slides-nginx:/usr/share/nginx/html/
+          docker exec slides-nginx nginx -s reload

nginx.conf

@@ -0,0 +1,10 @@
+server {
+    listen 80;
+    server_name _;
+    root /usr/share/nginx/html;
+    index index.html;
+
+    location / {
+        try_files $uri $uri/ $uri/index.html /index.html;
+    }
+}