fix(mcp): explicitly list entry points in tsconfig

tsgo with `include: ["src"]` sometimes skips standalone entry points
like stdio.ts that aren't imported by other files. This caused the
published npm package to be missing dist/stdio.js, breaking the
`openpencil-mcp` stdio binary.

Fixes #224 (npm publish issue)

packages/mcp/tsconfig.json

@@ -9,5 +9,5 @@
     "outDir": "dist",
     "rootDir": "src"
   },
-  "include": ["src"]
+  "include": ["src/index.ts", "src/server.ts", "src/stdio.ts"]
 }