chore: add change file for react-headless-components-preview exports fix

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: dmytrokirpa

change/@fluentui-react-headless-components-preview-c9669516-b75b-49e8-b52a-6a0eb4d02ea3.json

@@ -0,0 +1,7 @@
+{
+  "type": "patch",
+  "comment": "fix(react-headless-components-preview): add root \".\" exports specifier to fix Vite bundler resolution",
+  "packageName": "@fluentui/react-headless-components-preview",
+  "email": "dmytrokirpa@microsoft.com",
+  "dependentChangeType": "patch"
+}