feat(mcp): add package-backed ast-grep MCP

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

packages/ast-grep-mcp/src/cli.ts

@@ -0,0 +1,18 @@
+#!/usr/bin/env node
+import { argv, stderr } from "node:process";
+import { runMcpStdioServer } from "./mcp";
+
+async function main(): Promise<void> {
+  const [command = "mcp"] = argv.slice(2);
+  if (command === "mcp") {
+    await runMcpStdioServer();
+    return;
+  }
+  stderr.write("Usage: ast-grep-mcp [mcp]\n");
+  process.exitCode = 2;
+}
+
+main().catch((error: unknown) => {
+  stderr.write(`${error instanceof Error ? (error.stack ?? error.message) : String(error)}\n`);
+  process.exitCode = 1;
+});