feat(paperless): add paperless-ai with local LLM for auto-tagging

- paperless-ai deployment using clusterzx/paperless-ai
- LLM via local api-gateway (reasoning model, no auth - phase 3 pending)
- Paperless API token SOPS-encrypted
- Auto-tags new documents, 5min scan interval
- Adds 'ai-processed' tag to classified documents

k8s/apps/paperless/kustomization.yaml

@@ -11,6 +11,7 @@ resources:
   - backup-cronjob.yaml
   - adapter-configmap.yaml
   - rbac.yaml
+  - paperless-ai.yaml
 # postgres: paperless-db CNPG Cluster, deployed by k8s/infra/databases (wave 2,
 # before this app at wave 8) - not duplicated here. Same for the paperless-oidc
 # and paperless-minio-creds Secrets, written by PostSync provisioning Jobs in