feat(mcp): add netx-mcp package and HTTP stdio MCP

- Extract installable packages/netx-mcp (12 HTTP tools, mcp.json)

- Delegate netx_api.mcp to netx_mcp; keep legacy db_server shim

- Add docs/MCP.md, install payload, pyproject entry, tests

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

packages/netx-mcp/src/netx_mcp/server.py

@@ -0,0 +1,87 @@
+"""netx stdio MCP server (HTTP client to netx REST API).
+
+Environment:
+- ``NETX_API_URL``: netx REST base URL (default ``http://127.0.0.1:8890``)
+- ``NETX_API_TOKEN``: optional Bearer token
+- ``NETX_LANG``: ``zh`` or ``en`` for localized API responses
+"""
+
+from __future__ import annotations
+
+import json
+import sys
+from typing import Any
+
+from netx_mcp.http_tools import HTTP_MCP_TOOLS, call_http_tool
+
+
+def _ensure_utf8_stdio() -> None:
+    """MCP stdio must be UTF-8; Windows defaults to GBK and breaks the host reader."""
+    for stream in (sys.stdin, sys.stdout, sys.stderr):
+        if stream is None or not hasattr(stream, "reconfigure"):
+            continue
+        try:
+            stream.reconfigure(encoding="utf-8", errors="replace")
+        except Exception:
+            pass
+
+
+def _ok(rid: Any, result: dict[str, Any]) -> None:
+    sys.stdout.write(json.dumps({"jsonrpc": "2.0", "id": rid, "result": result}, ensure_ascii=False) + "\n")
+    sys.stdout.flush()
+
+
+def _err(rid: Any, code: int, message: str) -> None:
+    sys.stdout.write(
+        json.dumps({"jsonrpc": "2.0", "id": rid, "error": {"code": code, "message": message}}, ensure_ascii=False)
+        + "\n"
+    )
+    sys.stdout.flush()
+
+
+def run_stdio_loop() -> None:
+    for line in sys.stdin:
+        raw = line.strip()
+        if not raw:
+            continue
+        try:
+            req = json.loads(raw)
+        except Exception:
+            continue
+        rid = req.get("id")
+        method = str(req.get("method") or "")
+        params = req.get("params") if isinstance(req.get("params"), dict) else {}
+
+        try:
+            if method == "initialize":
+                _ok(
+                    rid,
+                    {
+                        "protocolVersion": "2024-11-05",
+                        "capabilities": {"tools": {}},
+                        "serverInfo": {"name": "netx-mcp", "version": "0.2.0", "mode": "http"},
+                    },
+                )
+                continue
+            if method == "notifications/initialized":
+                continue
+            if method == "tools/list":
+                _ok(rid, {"tools": HTTP_MCP_TOOLS})
+                continue
+            if method == "tools/call":
+                name = str(params.get("name") or "")
+                args = params.get("arguments") if isinstance(params.get("arguments"), dict) else {}
+                _ok(rid, call_http_tool(name, args))
+                continue
+            _err(rid, -32601, f"method not found: {method}")
+        except Exception as exc:
+            _err(rid, -32000, str(exc))
+
+
+def main() -> None:
+    _ensure_utf8_stdio()
+    run_stdio_loop()
+
+
+if __name__ == "__main__":
+    main()