feat: update PostgreSQL MCP schema to use DATABASE_URL environment variable

Author: zhujian0805

code_assistant_manager/mcp/registry/servers/postgresql.json

@@ -34,10 +34,7 @@
         "-y",
         "@modelcontextprotocol/server-postgres",
         "${DATABASE_URL}"
-      ],
-      "env": {
-        "DATABASE_URL": "${DATABASE_URL}"
-      }
+      ]
     },
     "docker": {
       "type": "docker",
@@ -50,10 +47,7 @@
         "DATABASE_URL",
         "mcp/postgres",
         "${DATABASE_URL}"
-      ],
-      "env": {
-        "DATABASE_URL": "${DATABASE_URL}"
-      }
+      ]
     }
   },
   "tools": [