feat: improve Docker deployment and Dify API configuration

- Use environment variables for Dify API key/URL
- Add host.docker.internal support in docker-compose
- Add DATABASE_URL env and prisma db push to Dockerfile
- Clean up test/requirement files and add deployment docs

mysite1.conf

@@ -0,0 +1,15 @@
+server {
+    listen 88;
+    server_name _;
+    location / {
+        proxy_pass http://127.0.0.1:3000;
+        proxy_http_version 1.1;
+        proxy_set_header Upgrade $http_upgrade;
+        proxy_set_header Connection 'upgrade';
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto $scheme;
+        proxy_cache_bypass $http_upgrade;
+    }
+}