Restructure compose mirror: stacks/ grouped by purpose, not by host

Replaces rocky-docker-lxc/, caddy-vm/, monitoring-vm/, and automation/
with a single stacks/ tree grouped by function (identity-and-security,
platform, media, productivity, dev-tools) - 55 stacks total, every one
a real directory in the private repos today.

Resolves all outstanding drift: adds Wazuh (previously entirely
missing), Firefly III and Postiz (never mirrored), the internal-zone
Caddy instance and the Cron Scheduler's separate NocoDB instance
(both previously conflated with their counterparts under one shared
folder); renames Calibre-Web to calibre-web-automated and splits
Kodi-MariaDB into kodi + mariadb-latest to match what the private
repos actually run now; drops the decommissioned NetBox stack.

Also removes automation/iac/old-content/ and
automation/ansible/old-playbooks/ in the same pass - both folders
were entirely stale content describing a superseded architecture
(GitLab instead of Gitea, HAProxy+mTLS SSO instead of the current
Caddy+Authentik setup), now replaced by docs/iac-pipeline.md.

stacks/platform/dockhand/docker-compose.yaml

@@ -0,0 +1,49 @@
+services:
+  socket-proxy:
+    image: tecnativa/docker-socket-proxy
+    container_name: dockhand-socket-proxy
+    restart: always
+    environment:
+      # Required for Dockhand core functionality
+      - CONTAINERS=1
+      - IMAGES=1
+      - NETWORKS=1
+      - VOLUMES=1
+      - EVENTS=1
+      - POST=1
+      - DELETE=1
+      # Required for dashboard host info and disk usage
+      - INFO=1
+      - SYSTEM=1
+      # Required for vulnerability scanning
+      - ALLOW_START=1
+      - ALLOW_STOP=1
+      - ALLOW_RESTARTS=1
+      # Optional: enable for terminal access
+      - EXEC=1
+    volumes:
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+    networks:
+      - dockhand-net
+
+  dockhand:
+    image: fnsys/dockhand:latest
+    container_name: dockhand
+    restart: always
+    depends_on:
+      - socket-proxy
+    environment:
+      - PUID=1000
+      - PGID=1000
+    group_add:
+      - "996"
+    ports:
+      - ${HTTP_PORT}:3000
+    volumes:
+      - /path/to/dockhand/dockhand_data:/app/data
+    networks:
+      - dockhand-net
+
+networks:
+  dockhand-net:
+    external: true