feat: rewrite nginx files

deploy/nginx.conf.http.example

@@ -0,0 +1,51 @@
+# nginx reverse proxy for the LPRA server.
+# TLS is terminated here; the Go server listens on 127.0.0.1:8091.
+#
+# Put this in /etc/nginx/sites-available/lp_agent and symlink it into
+# sites-enabled, then:  sudo nginx -t && sudo systemctl reload nginx
+#
+# Agents connect by WebSocket (from 0.1.0), with HTTP long polling to fall
+# back on; the browser uses plain HTTP. The settings that matter:
+#   - Upgrade / Connection headers -> let the agents' WebSocket through
+#   - proxy_buffering off          -> deliver long-poll responses immediately
+#   - proxy_read_timeout 300s      -> longer than the 25s long-poll hold
+#
+# NOTE: proxy_pass MUST start with "http://". A bare "proxy_pass 127.0.0.1:8091;"
+# causes nginx error:  [emerg] invalid URL prefix.
+
+# "Connection: upgrade" for a WebSocket, "close" for everything else.
+
+
+map $http_upgrade $connection_upgrade {
+    default upgrade;
+    ''      close;
+}
+
+server {
+    listen 80;
+    server_name example.ru;
+
+    client_max_body_size 120m;
+
+    location / {
+        proxy_pass http://127.0.0.1:8091;
+
+        proxy_http_version 1.1;
+        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;
+        # Agents' WebSocket.
+        proxy_set_header Upgrade           $http_upgrade;
+        proxy_set_header Connection        $connection_upgrade;
+
+        # Long-poll behaviour: no buffering, generous read timeout.
+        proxy_buffering     off;
+        proxy_cache         off;
+        # Pass uploads on as they arrive: the speed test through the browser
+        # times them on the client.
+        proxy_request_buffering off;
+        proxy_read_timeout  300s;
+        proxy_send_timeout  300s;
+    }
+}