Add fuelish API; protect the host against memory exhaustion

- fuelish role: receipt OCR API at fuelish.ladkau.de, API-key auth, shared
  Ollama model and request options
- base: 4 GB swap file; act_runner: job containers capped at 4 GB without swap
- docs and vault/service checks updated

scripts/check-services.sh

@@ -18,6 +18,7 @@ CHECKS=(
   "https://k8s.ladkau.de 200 10"
   "https://vault.ladkau.de 200 10"
   "https://dl.ladkau.de 200 10"
+  "https://fuelish.ladkau.de/health 200 10"
   "https://agent.ladkau.de 401 10"
   "https://agent.ladkau.de/chat 401 10"
 )

scripts/check-vault.sh

@@ -45,6 +45,7 @@ required_scalars = [
     "roundcube_des_key",
     "vaultwarden_admin_token",
     "n8n_encryption_key",
+    "fuelish_api_key",
     "searxng_secret_key",
     "smtp_user",
     "smtp_password",