Add healthchecks and resource constraints to all services

Added healthchecks:
- adminer: PHP file_get_contents check
- authentik_server: ak healthcheck command
- authentik_redis: redis-cli ping
- paperless_redis: redis-cli ping
- paperless_webserver: curl localhost:8000
- n8n: wget healthz endpoint
- traefik: wget ping endpoint (with --ping enabled)
- tracker-nginx: curl localhost:80

Added resource limits:
- adminer: 512M limit, 128M reservation
- authentik_server: 1G/1 CPU limit, 512M reservation
- authentik_worker: 1G/1 CPU limit, 512M reservation
- authentik_redis: 512M limit, 128M reservation
- paperless_redis: 512M limit, 128M reservation
- paperless_webserver: 2G/2 CPU limit, 1G reservation
- traefik: 512M/0.5 CPU limit, 256M reservation
- tracker-nginx: 256M limit, 64M reservation

All services now have proper health monitoring and resource constraints
to prevent resource exhaustion and improve reliability.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

stacks/core/traefik/stack.yml

@@ -4,6 +4,7 @@ services:
     command:
     - --api.dashboard=true
     - --api.insecure=true
+    - --ping=true
     - --entrypoints.web.address=:80
     - --entrypoints.websecure.address=:443
     - --entrypoints.web.http.redirections.entrypoint.to=websecure
@@ -34,12 +35,24 @@ services:
     - cloudflare_api_token
     networks:
     - homelab
+    healthcheck:
+      test: ["CMD", "wget", "--quiet", "--tries=1", "--spider", "http://localhost:8080/ping"]
+      interval: 30s
+      timeout: 5s
+      retries: 3
+      start_period: 30s
     deploy:
       mode: replicated
       replicas: 1
       placement:
         constraints:
         - node.hostname == p0
+      resources:
+        limits:
+          memory: 512M
+          cpus: '0.5'
+        reservations:
+          memory: 256M
       labels:
       - "traefik.enable=true"
       - "traefik.http.routers.traefik.rule=Host(`proxy.frostlabs.me`)"