feat: add Nginx, Windows and Firefox brand icons

- Nginx: siNginx (#009639) — keywords: nginx
- Windows: custom icon (#0078D4) — keywords: windows, win10, win11, winserver, windows server
- Firefox: siFirefox (#FF7139) — keywords: firefox
- Apache/Apache2 was already supported (no change needed)

Update README (en/fr/es) brand tables accordingly.

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

README.es.md

@@ -307,6 +307,7 @@ Pueden aparecer varios logos simultáneamente si coinciden varias palabras clave
 | Red | OpenWrt | `openwrt` |
 | Seguridad de red | Fortinet / FortiGate | `fortinet`, `fortigate`, `fortios`, `fortimanager`, `fortiauthenticator` |
 | Web / proxy | Apache | `apache`, `apache2`, `httpd` |
+| Web / proxy | Nginx | `nginx` |
 | Web / proxy | Traefik | `traefik` |
 | Web / proxy | Apache Guacamole | `guacamole` |
 | Bastión | Bastión / jump host | `bastion`, `jumphost`, `jump host`, `jump server`, `teleport`, `bastillion` |
@@ -346,6 +347,7 @@ Pueden aparecer varios logos simultáneamente si coinciden varias palabras clave
 | Logs / Trazas | Jaeger | `jaeger` |
 | Logs / Trazas | OpenTelemetry | `opentelemetry`, `otel` |
 | Ecosistema Apple | Apple | `apple`, `iphone`, `ipad`, `ipados`, `macbook`, `imac`, `mac mini`, `mac pro`, `mac studio`, `macos`, `mac os`, `ios`, `icloud`, `airpods`, `airdrop` |
+| OS | Windows | `windows`, `win10`, `win11`, `winserver`, `windows server` |
 | OS | Debian | `debian` |
 | OS | Ubuntu | `ubuntu` |
 | Automatización | Ansible | `ansible` |
@@ -353,6 +355,7 @@ Pueden aparecer varios logos simultáneamente si coinciden varias palabras clave
 | Servidores | HP | `proliant`, `ilo`, `hewlett` |
 | SBC / DIY | Raspberry Pi | `raspberry`, `raspberrypi`, `rpi`, `raspi` |
 | SBC / DIY | Arduino | `arduino` |
+| Navegador | Firefox | `firefox` |
 | Escritorio | KDE / Plasma | `kde`, `plasma`, `kde desktop` |
 | Herramientas | Excalidraw | `excalidraw` |
 | Self-hosted | Nextcloud | `nextcloud` |