Add AI review workflow for Paperless documents

.env.portainer.example

@@ -42,3 +42,17 @@ WATCHTOWER_ENABLE=false
 
 # Optional fixed iCal token.
 # ICAL_SECRET=replace-with-long-random-token
+
+# Optional AI document analysis.
+# AI_ENABLED=false
+# AI_PROVIDER=openai
+# AI_BASE_URL=https://api.openai.com/v1
+# AI_MODEL=gpt-4o-mini
+# AI_API_KEY=replace-with-ai-api-key
+# AI_SYSTEM_PROMPT=
+# AI_TIMEOUT_SECONDS=60
+# AI_MAX_TOKENS=2000
+
+# Optional paperless workflow webhook secret.
+# Paperless should send this value as x-contract-companion-secret.
+# PAPERLESS_WEBHOOK_SECRET=replace-with-long-random-webhook-secret