feat(mcp): integrate netx via netx_mcp and improve MCP install

- Gate builtin netx tools; ops docs/skills use mcp__netx__*

- Import Cursor mcpServers JSON; pass env_schema defaults to subprocess

- Allow source_type=local; UTF-8 MCP stdio on Windows

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/test_mcp_env_defaults.py

@@ -0,0 +1,41 @@
+"""MCP subprocess env: env_schema defaults from registry (Cursor mcpServers.env import)."""
+
+from __future__ import annotations
+
+import os
+import unittest
+from unittest.mock import patch
+
+from runtime.tools.mcp.runtime import McpProcessRuntime
+
+
+class McpEnvDefaultsTests(unittest.TestCase):
+    @patch("runtime.operations.mcp_env.mcp_local_env_merged", return_value={})
+    def test_env_schema_default_used_when_not_in_os_environ(self, _mock: object) -> None:
+        os.environ.pop("NETX_API_URL", None)
+        try:
+            env = McpProcessRuntime._build_runtime_env(
+                ["NETX_API_URL"],
+                {"NETX_API_URL": "http://10.0.0.5:8890"},
+            )
+            assert env is not None
+            self.assertEqual(env.get("NETX_API_URL"), "http://10.0.0.5:8890")
+        finally:
+            pass
+
+    @patch("runtime.operations.mcp_env.mcp_local_env_merged", return_value={})
+    def test_mcp_local_and_os_environ_override_schema_default(self, _mock: object) -> None:
+        os.environ["NETX_API_URL"] = "http://from-host:8890"
+        try:
+            env = McpProcessRuntime._build_runtime_env(
+                ["NETX_API_URL"],
+                {"NETX_API_URL": "http://from-schema:8890"},
+            )
+            assert env is not None
+            self.assertEqual(env.get("NETX_API_URL"), "http://from-host:8890")
+        finally:
+            os.environ.pop("NETX_API_URL", None)
+
+
+if __name__ == "__main__":
+    unittest.main()