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/systemd/rss2-discovery.service

@@ -0,0 +1,26 @@
+[Unit]
+Description=RSS2 Discovery de Feeds (Go)
+After=network.target postgresql.service
+Requires=postgresql.service
+
+[Service]
+Type=simple
+User=rss2
+Group=rss2
+WorkingDirectory=/opt/rss2
+EnvironmentFile=/opt/rss2/.env
+Environment=DISCOVERY_INTERVAL=900
+Environment=DISCOVERY_BATCH=10
+Environment=MAX_FEEDS_PER_URL=5
+ExecStart=/opt/rss2/bin/discovery
+Restart=always
+RestartSec=10
+StandardOutput=journal
+StandardError=journal
+SyslogIdentifier=rss2-discovery
+
+MemoryMax=512M
+CPUQuota=100%
+
+[Install]
+WantedBy=multi-user.target