feat: Multi-user system with PostgreSQL - WIP temporary save

backend_api_python/env.example

@@ -8,6 +8,13 @@ SECRET_KEY=quantdinger-secret-key-change-me
 ADMIN_USER=quantdinger
 ADMIN_PASSWORD=123456
 
+# =========================
+# Demo Mode
+# =========================
+# Set to true to enable read-only mode for public demo.
+# Blocks all POST/PUT/DELETE requests except login.
+IS_DEMO_MODE=false
+
 # =========================
 # Network / App
 # =========================
@@ -16,12 +23,13 @@ PYTHON_API_PORT=5000
 PYTHON_API_DEBUG=False
 
 # =========================
-# Database (SQLite)
+# Database Configuration (PostgreSQL)
 # =========================
-# 主库文件路径（可选）
-# - 不设置时，默认使用：backend_api_python/data/quantdinger.db
-# - Docker 推荐：/app/data/quantdinger.db
-SQLITE_DATABASE_FILE=
+# PostgreSQL connection URL (required for multi-user mode)
+# Format: postgresql://user:password@host:port/dbname
+# Docker: uses this default, no changes needed
+# Local: change 'postgres' to 'localhost' and update password
+DATABASE_URL=postgresql://quantdinger:quantdinger123@postgres:5432/quantdinger
 
 # =========================
 # Pending orders worker (optional)