feat(arje): cadena DM activa — kmod virtio_gpu + carmen-dm en arje-prod

- seed arje-prod gana dos Cards antes de getty-tty1:
  * kmod-gpu (OneShot): modprobe virtio_gpu — pone /dev/dri/card0
    listo antes de que el compositor intente abrir DRM/KMS.
  * carmen-dm (Restart): /usr/bin/mirada-compositor --greeter --drm,
    con MIRADA_GREETER_BIN apuntando a /usr/bin/mirada-greeter.

- install-arje-as-init.sh gana paso 1b: build nativo (no-musl) de
  mirada-compositor y mirada-greeter. GPUI/Mesa/EGL son dinámicos
  contra glibc — la cadena DM no puede vivir en el binario musl
  estático de arje-zero. Si el build falla por dev-libs ausentes,
  se imprime la lista de paquetes Fedora que faltan y se sigue
  (la instalación de arje-zero no se rompe).

- En el paso de instalación, los binarios del compositor se copian
  a /usr/bin/ sólo si el build de paso 1b tuvo éxito; ldconfig
  comprueba libEGL en runtime y avisa si falta.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

seeds/arje-prod.card.json

@@ -302,6 +302,47 @@
       "lifecycle": "daemon", "priority": "high",
       "flow": { "input": [], "output": [] }, "genesis": []
     },
+    {
+      "schema_version": 1,
+      "id": "01J8YVKZQ0M0M0M0M0M0M0M0K0",
+      "lineage": null,
+      "label": "kmod-gpu",
+      "provides": [], "requires": [],
+      "permissions": { "networking": "none", "filesystem": "read-write", "ipc": { "allow": [] }, "processes": true },
+      "soma": { "namespaces": {"mount":false,"pid":false,"net":false,"uts":false,"ipc":false,"user":false,"cgroup":false},
+                "rlimits": {"mem_bytes":null,"nproc":null,"nofile":null},
+                "cgroup": {"path":"ente.slice/kmod","cpu_weight":null,"io_weight":null},
+                "cpu_affinity": null },
+      "payload": { "Native": { "exec": "/usr/sbin/modprobe", "argv": ["virtio_gpu"], "envp": [] } },
+      "supervision": "OneShot",
+      "lifecycle": "oneshot",
+      "priority": "critical",
+      "flow": { "input": [], "output": [] }, "genesis": []
+    },
+    {
+      "schema_version": 1,
+      "id": "01J8YVKZQ0M0M0M0M0M0M0M0CM",
+      "lineage": null,
+      "label": "carmen-dm",
+      "provides": [], "requires": [],
+      "permissions": { "networking": "loopback", "filesystem": "read-write", "ipc": { "allow": [] }, "processes": true },
+      "soma": { "namespaces": {"mount":false,"pid":false,"net":false,"uts":false,"ipc":false,"user":false,"cgroup":false},
+                "rlimits": {"mem_bytes":null,"nproc":null,"nofile":null},
+                "cgroup": {"path":"ente.slice/carmen","cpu_weight":null,"io_weight":null},
+                "cpu_affinity": null },
+      "payload": { "Native": {
+        "exec": "/usr/bin/mirada-compositor",
+        "argv": ["--greeter", "--drm"],
+        "envp": [
+          ["PATH", "/usr/local/bin:/usr/bin:/usr/sbin:/sbin:/bin"],
+          ["XDG_RUNTIME_DIR", "/run"],
+          ["MIRADA_GREETER_BIN", "/usr/bin/mirada-greeter"]
+        ]
+      } },
+      "supervision": { "Restart": { "initial": 2000, "max": 60000 } },
+      "lifecycle": "daemon", "priority": "high",
+      "flow": { "input": [], "output": [] }, "genesis": []
+    },
     {
       "schema_version": 1,
       "id": "01J8YVKZQ0M0M0M0M0M0M0M0G0",