fix: add missing environment setup steps to Docker quickstart

- Set NODE_ENV=production in .env.example
- Add AUTH_SECRET generation and env file copy to Docker quickstart
- Resolve issues #122: missing AUTH_SECRET and NODE_ENV causing startup failures

Author: chriswritescode-dev

.env.example

@@ -8,7 +8,7 @@
 PORT=5001
 HOST=0.0.0.0
 CORS_ORIGIN=http://localhost:5173
-NODE_ENV=development
+NODE_ENV=production
 LOG_LEVEL=info
 
 # ============================================

docs/getting-started/quickstart.md

@@ -9,6 +9,8 @@ Get up and running with OpenCode Manager in minutes.
     ```bash
     git clone https://github.com/chriswritescode-dev/opencode-manager.git
     cd opencode-manager
+    cp .env.example .env
+    echo "AUTH_SECRET=$(openssl rand -base64 32)" >> .env
     docker-compose up -d
     ```