feat(deploy): despliegue nativo Debian sin Docker

- Elimina todos los Dockerfiles y docker-compose.yml
- Elimina scripts Docker (start_docker, reset_and_deploy, deploy-clean)
- Agrega deploy/debian/ con despliegue nativo via systemd:
  - install.sh: instalacion completa en Debian (PostgreSQL, Redis,
    Qdrant binario, Go, Python venv, nginx, frontend compilado)
  - build.sh: recompila binarios Go y frontend sin reinstalar
  - env.example: variables de entorno sin referencias Docker
  - nginx.conf: sirve React estatico + proxy al API Go en localhost
  - systemd/*.service: 16 servicios (8 Go + 7 Python + Qdrant)

Todos los hostnames Docker (db, redis, qdrant) reemplazados por 127.0.0.1

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

deploy/debian/nginx.conf

@@ -0,0 +1,91 @@
+user www-data;
+worker_processes auto;
+error_log /var/log/nginx/error.log warn;
+pid /run/nginx.pid;
+
+events {
+    worker_connections 2048;
+    use epoll;
+}
+
+http {
+    include /etc/nginx/mime.types;
+    default_type application/octet-stream;
+
+    log_format main '$remote_addr - $remote_user [$time_local] "$request" '
+                    '$status $body_bytes_sent "$http_referer" '
+                    '"$http_user_agent" "$http_x_forwarded_for"';
+
+    access_log /var/log/nginx/access.log main;
+
+    sendfile on;
+    tcp_nopush on;
+    tcp_nodelay on;
+    keepalive_timeout 65;
+    types_hash_max_size 2048;
+    client_max_body_size 100M;
+
+    gzip on;
+    gzip_vary on;
+    gzip_proxied any;
+    gzip_comp_level 6;
+    gzip_types text/plain text/css text/javascript
+               application/json application/javascript
+               application/xml text/xml;
+
+    # Go API backend (proceso nativo en localhost)
+    upstream api_backend {
+        server 127.0.0.1:8080;
+        keepalive 32;
+    }
+
+    server {
+        listen 8001;
+        server_name _;
+
+        client_body_timeout 60s;
+        client_header_timeout 60s;
+        send_timeout 300s;
+
+        # Frontend React (archivos estaticos compilados)
+        root /opt/rss2/frontend/dist;
+        index index.html;
+
+        location / {
+            try_files $uri $uri/ /index.html;
+        }
+
+        # Imagenes Wikipedia servidas directamente
+        location /wiki-images/ {
+            alias /opt/rss2/data/wiki_images/;
+            expires 7d;
+            add_header Cache-Control "public, immutable";
+        }
+
+        # Proxy al API Go
+        location /api/ {
+            proxy_pass http://api_backend/api/;
+            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;
+            proxy_set_header Connection "";
+
+            proxy_connect_timeout 60s;
+            proxy_send_timeout 300s;
+            proxy_read_timeout 300s;
+        }
+
+        location /health {
+            access_log off;
+            return 200 "ok";
+        }
+
+        location ~ /\. {
+            deny all;
+            access_log off;
+            log_not_found off;
+        }
+    }
+}