fix: rename AI postgres service to avoid conflict with core

Changed service name from 'postgres' to 'ai_postgres' to avoid naming
conflict with the core PostgreSQL service in Docker Compose include.

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

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

ai/compose.yaml

@@ -1,6 +1,6 @@
 services:
   # PostgreSQL with pgvector for AI/RAG workloads
-  postgres:
+  ai_postgres:
     image: ${AI_POSTGRES_IMAGE:-pgvector/pgvector:pg16}
     container_name: ${AI_COMPOSE_PROJECT_NAME}_postgres
     restart: unless-stopped
@@ -31,7 +31,7 @@ services:
       TZ: ${TIMEZONE:-Europe/Berlin}
 
       # Database configuration
-      DATABASE_URL: postgresql://${AI_DB_USER}:${AI_DB_PASSWORD}@postgres:5432/${AI_DB_NAME}
+      DATABASE_URL: postgresql://${AI_DB_USER}:${AI_DB_PASSWORD}@ai_postgres:5432/${AI_DB_NAME}
 
       # OpenAI API configuration (for Claude via Anthropic API)
       OPENAI_API_BASE_URLS: ${AI_OPENAI_API_BASE_URLS:-https://api.anthropic.com/v1}
@@ -64,7 +64,7 @@ services:
     volumes:
       - ai_webui_data:/app/backend/data
     depends_on:
-      - postgres
+      - ai_postgres
     networks:
       - compose_network
     labels: