feat(installer): add .env.example with documented variables

Reference .env file documenting all configuration variables across both
deployment modes, with section headers for compose assembly, public access,
credentials, TLS, Docker, provisioning, and monitoring.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

installer/templates/.env.example

@@ -0,0 +1,88 @@
+# Cameleer Configuration
+# Copy this file to .env and fill in the values.
+# The installer generates .env automatically — this file is for reference.
+
+# ============================================================
+# Compose file assembly (set by installer)
+# ============================================================
+# SaaS:        docker-compose.yml:docker-compose.saas.yml
+# Standalone:  docker-compose.yml:docker-compose.server.yml
+# Add :docker-compose.tls.yml for custom TLS certificates
+# Add :docker-compose.monitoring.yml for external monitoring network
+COMPOSE_FILE=docker-compose.yml:docker-compose.saas.yml
+
+# ============================================================
+# Image version
+# ============================================================
+VERSION=latest
+
+# ============================================================
+# Public access
+# ============================================================
+PUBLIC_HOST=localhost
+PUBLIC_PROTOCOL=https
+
+# ============================================================
+# Ports
+# ============================================================
+HTTP_PORT=80
+HTTPS_PORT=443
+# Set to 0.0.0.0 to expose Logto admin console externally (default: localhost only)
+# LOGTO_CONSOLE_BIND=0.0.0.0
+LOGTO_CONSOLE_PORT=3002
+
+# ============================================================
+# PostgreSQL
+# ============================================================
+POSTGRES_USER=cameleer
+POSTGRES_PASSWORD=CHANGE_ME
+# SaaS: cameleer_saas, Standalone: cameleer
+POSTGRES_DB=cameleer_saas
+
+# ============================================================
+# ClickHouse
+# ============================================================
+CLICKHOUSE_PASSWORD=CHANGE_ME
+
+# ============================================================
+# Admin credentials (SaaS mode)
+# ============================================================
+SAAS_ADMIN_USER=admin
+SAAS_ADMIN_PASS=CHANGE_ME
+
+# ============================================================
+# Admin credentials (standalone mode)
+# ============================================================
+# SERVER_ADMIN_USER=admin
+# SERVER_ADMIN_PASS=CHANGE_ME
+# BOOTSTRAP_TOKEN=CHANGE_ME
+
+# ============================================================
+# TLS
+# ============================================================
+# Set to 1 to reject unauthorized TLS certificates (production)
+NODE_TLS_REJECT=0
+# Custom TLS certificate paths (inside container, set by installer)
+# CERT_FILE=/user-certs/cert.pem
+# KEY_FILE=/user-certs/key.pem
+# CA_FILE=/user-certs/ca.pem
+
+# ============================================================
+# Docker
+# ============================================================
+DOCKER_SOCKET=/var/run/docker.sock
+# GID of the docker socket — detected by installer, used for container group_add
+DOCKER_GID=0
+
+# ============================================================
+# Provisioning images (SaaS mode only)
+# ============================================================
+# CAMELEER_SAAS_PROVISIONING_SERVERIMAGE=gitea.siegeln.net/cameleer/cameleer-server:latest
+# CAMELEER_SAAS_PROVISIONING_SERVERUIIMAGE=gitea.siegeln.net/cameleer/cameleer-server-ui:latest
+
+# ============================================================
+# Monitoring (optional)
+# ============================================================
+# External Docker network name for Prometheus scraping.
+# Only needed when docker-compose.monitoring.yml is in COMPOSE_FILE.
+# MONITORING_NETWORK=prometheus