Added docs for sandbox git commands (#87)

* docs for git operations

Author: matthewlouisbrockman

docs.json

@@ -152,6 +152,12 @@
               "docs/commands/background"
             ]
           },
+          {
+            "group": "Git",
+            "pages": [
+              "docs/git"
+            ]
+          },
           {
             "group": "MCP Gateway",
             "pages": [
@@ -329,4 +335,4 @@
       "permanent": true
     }
   ]
-}
+}