refactor(oci): remove the shell entry point nothing runs

`oci/proxmenux-oci.sh` was installed on every Proxmox host and used on
none of them. The menu entry goes straight to the orchestrator:
scripts/oci/oci_manager_apps.sh runs `python3 -m proxmenux_oci` with
PYTHONPATH pointing at the engine.

Its only remaining caller was a message telling the reader to open it on
the Proxmox host — which is not how anyone gets in, and is what sent one
there to run it. That message now names the menu entry.

It could not be fetched and run either: it needs requirements.txt and
src/ beside it, so `wget | bash` resolved its own directory to the
working directory and failed on a path nobody chose. Making that work
would mean writing a second installer next to the one that already
ships the engine.

What it did offer was a virtualenv for a contributor generating the
catalog. The README now gives the direct invocation and names the two
distribution packages it needs.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

lang/es.json

@@ -6209,7 +6209,7 @@
   "This installation will:": "Esta instalación:",
   "This installer will:": "Este instalador:",
   "This interface is configured but doesn't exist physically": "Esta interfaz está configurada pero no existe físicamente.",
-  "This interface runs on the Proxmox node as root. Open proxmenux-oci.sh on the Proxmox host.": "Esta interfaz se ejecuta en el nodo Proxmox como root. Abre proxmenux-oci.sh en el host Proxmox.",
+  "This interface runs on the Proxmox node as root. Open OCI manager Apps from the ProxMenux menu on the Proxmox host.": "Esta interfaz se ejecuta en el nodo Proxmox como root. Abre OCI manager Apps desde el menú de ProxMenux en el host Proxmox.",
   "This is IRREVERSIBLE.": "Esto es IRREVERSIBLE.",
   "This is a destructive action": "Esta es una acción destructiva.",
   "This is a simple configuration change": "Este es un cambio de configuración simple.",