monitoring: capture compute6 Diun compose (closes audit visibility gap)

Deployed 2026-06-30 to close compute6's image-update blind spot; was running on
compute6 but not tracked. Includes the required security_opt apparmor=unconfined
(compute6 host norm) without which Diun can't read the docker socket.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

monitoring/diun-compute6/README.md

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+# Diun on compute6
+
+Closes the compute6 image-update-visibility gap found in the 2026-06-30 drift audit
+(node01/02/media-server already ran Diun; compute6 did not). Mirrors the node01/02
+crazymax/diun pattern; watches compute6's ~10 local containers via the docker socket,
+notifies the same HA webhook.
+
+Deploys to compute6 at `~/diun/docker-compose.yml`.
+
+**compute6 quirk:** `security_opt: apparmor=unconfined` is REQUIRED here — compute6's
+default AppArmor profile blocks the container's docker-socket access (every compute6
+container runs unconfined for this reason). Without it Diun logs "permission denied"
+on the socket and finds 0 images.

monitoring/diun-compute6/docker-compose.yml

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+services:
+  # ============================================================
+  # DIUN - Docker Image Update Notifier (compute6)
+  # ============================================================
+  # Mirrors the node01/02 pattern (crazymax/diun) to close the compute6
+  # image-update visibility gap. Watches compute6's local containers via the
+  # docker socket; notifies the same HA webhook -> mobile_app_tomcell.
+  # No traefik_public here (doesn't exist on compute6) -> default bridge;
+  # Diun needs only the socket + outbound to registries and .100:8123.
+  # ============================================================
+  diun:
+    image: crazymax/diun:latest
+    container_name: diun
+    restart: unless-stopped
+    mem_limit: 256m
+    cpus: 0.5
+    environment:
+      - TZ=America/Chicago
+      - LOG_LEVEL=info
+      - LOG_JSON=false
+      - DIUN_WATCH_WORKERS=20
+      - DIUN_WATCH_SCHEDULE=0 8 * * *
+      - DIUN_WATCH_FIRSTCHECKNOTIF=false
+      - DIUN_PROVIDERS_DOCKER=true
+      - DIUN_PROVIDERS_DOCKER_WATCHBYDEFAULT=true
+      - DIUN_NOTIF_WEBHOOK_ENDPOINT=http://192.168.99.100:8123/api/webhook/diun_image_update
+      - DIUN_NOTIF_WEBHOOK_METHOD=POST
+      - DIUN_NOTIF_WEBHOOK_HEADERS_CONTENT-TYPE=application/json
+    security_opt:
+      - apparmor=unconfined
+    volumes:
+      - ./data:/data
+      - /var/run/docker.sock:/var/run/docker.sock:ro