fix: use plain bin name mcp-multi-root-git (strip scope prefix)

npm does not support @scope/name as a bin key; the binary must be
a plain identifier. npx @rethunk/mcp-multi-root-git still works.

Author: AlbinoGeek

package.json

@@ -13,7 +13,7 @@
     "LICENSE"
   ],
   "bin": {
-    "@rethunk/mcp-multi-root-git": "dist/server.js"
+    "mcp-multi-root-git": "dist/server.js"
   },
   "exports": {
     ".": {