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were entirely stale content describing a superseded architecture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/home-assistant/docker-compose.yaml

@@ -0,0 +1,56 @@
+services:
+  homeassistant:
+    container_name: home-assistant
+    image: ghcr.io/home-assistant/home-assistant:stable
+    volumes:
+      - /path/to/home-assistant/config:/config
+      - /etc/localtime:/etc/localtime:ro
+    environment:
+      - PUID=${PUID}
+      - PGID=${PGID}
+      - TZ=${TZ}
+    restart: unless-stopped
+    ports:
+      - "${HTTP_PORT}:8123"
+    depends_on:
+      homeassistant-db:
+        condition: service_healthy
+    privileged: true
+    healthcheck:
+      test: [
+          "CMD-SHELL",
+          "curl -fsS -o /dev/null -w '%{http_code}' http://127.0.0.1:8123/api/
+          | grep -q 401",
+        ]
+      interval: 30s
+      timeout: 10s
+      retries: 10
+      start_period: 90s
+    networks:
+      - home-assistant-net
+
+  homeassistant-db:
+    container_name: homeassistant-db
+    image: postgres:latest
+    restart: unless-stopped
+    environment:
+      - POSTGRES_USER=${POSTGRES_USER}
+      - POSTGRES_PASSWORD=${POSTGRES_PASSWORD}
+      - POSTGRES_DB=${POSTGRES_DB}
+      - POSTGRES_INITDB_ARGS=--encoding=UTF-8 --locale=en_US.UTF-8
+    volumes:
+      - /path/to/home-assistant/schemas:/var/lib/postgresql
+    security_opt:
+      - no-new-privileges:true
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U ${POSTGRES_USER} -d ${POSTGRES_DB}"]
+      interval: 5s
+      timeout: 5s
+      retries: 10
+      start_period: 10s
+    networks:
+      - home-assistant-net
+
+networks:
+  home-assistant-net:
+    external: true