feat: add Docker Compose production stack with Traefik + Logto

7-service stack: Traefik (reverse proxy), PostgreSQL (shared),
Logto (identity), cameleer-saas (control plane), cameleer3-server
(observability), ClickHouse (traces). ForwardAuth middleware for
tenant-aware routing to cameleer3-server.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker/init-databases.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+set -e
+
+psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" <<-EOSQL
+    CREATE DATABASE logto;
+    GRANT ALL PRIVILEGES ON DATABASE logto TO $POSTGRES_USER;
+EOSQL