chore(docs): add link to dotenvx management detail (supabase#36709)

* chore(docs): add link to dotenvx management detail

* Update apps/docs/content/guides/local-development/managing-config.mdx

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: avallete

apps/docs/content/guides/local-development/managing-config.mdx

@@ -56,3 +56,13 @@ client_id = "env(GITHUB_CLIENT_ID)"
 secret = "env(GITHUB_SECRET)"
 redirect_uri = "" # Overrides the default auth redirectUrl.
 ```
+
+### Going further
+
+For more advanced secrets management workflows, including:
+
+- **Using dotenvx for encrypted secrets**: Learn how to securely manage environment variables across different branches and environments
+- **Branch-specific secrets**: Understand how to manage secrets for different deployment environments
+- **Encrypted configuration values**: Use encrypted values directly in your `config.toml`
+
+See the [Managing secrets for branches](/docs/guides/deployment/branching#managing-secrets-for-branches) section in our branching documentation, or check out the [dotenvx example repository](https://github.com/supabase/supabase/blob/master/examples/slack-clone/nextjs-slack-clone-dotenvx/README.md) for a complete implementation.