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were entirely stale content describing a superseded architecture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/productivity/bookstack/docker-compose.yaml

@@ -0,0 +1,63 @@
+---
+services:
+  bookstack:
+    image: lscr.io/linuxserver/bookstack:latest
+    container_name: bookstack
+    environment:
+      - PUID=${PUID}
+      - PGID=${PGID}
+      - TZ=${TZ}
+      - APP_URL=https://subdomain.example.com
+      - DB_HOST=bookstack_db
+      - DB_PORT=${DB_PORT}
+      - DB_USER=${DB_USER}
+      - DB_PASS=${DB_PASS}
+      - DB_DATABASE=${DB_DATABASE}
+      - APP_DEFAULT_DARK_MODE=true
+    volumes:
+      - /path/to/bookstack/bookstack_app_data:/config
+    ports:
+      - ${HTTP_PORT}:80
+    restart: unless-stopped
+    depends_on:
+      bookstack_db:
+        condition: service_healthy
+    healthcheck:
+      test: ["CMD-SHELL", "wget -qO- http://127.0.0.1:80/ || exit 1"]
+      interval: 15s
+      timeout: 5s
+      retries: 5
+      start_period: 30s
+    networks:
+      - bookstack-net
+
+  bookstack_db:
+    image: lscr.io/linuxserver/mariadb:latest
+    container_name: bookstack_db
+    environment:
+      - PUID=${PUID}
+      - PGID=${PGID}
+      - TZ=${TZ}
+      - MYSQL_ROOT_PASSWORD=${DB_ROOT_PASSWORD}
+      - MYSQL_DATABASE=${DB_DATABASE}
+      - MYSQL_USER=${DB_USER}
+      - MYSQL_PASSWORD=${DB_PASSWORD}
+    volumes:
+      - /path/to/bookstack/bookstack_db_data:/config
+    restart: unless-stopped
+    healthcheck:
+      test:
+        [
+          "CMD-SHELL",
+          "mysqladmin ping -h localhost -u${DB_USER} -p${DB_PASSWORD} || exit 1",
+        ]
+      interval: 10s
+      timeout: 5s
+      retries: 10
+      start_period: 20s
+    networks:
+      - bookstack-net
+
+networks:
+  bookstack-net:
+    external: true