Chore: regenerate docs navigation

Auto-generated-by: update-generated-files-action; https://github.com/OpenRouterTeam/python-sdk/actions/runs/40806145298

Author: github-actions[bot]

docs/docs.json

@@ -35,6 +35,7 @@
       "sdks/organization/README",
       "sdks/presets/README",
       "sdks/privateendpoints/README",
+      "sdks/privateproviders/README",
       "sdks/providers/README",
       "sdks/rerank/README",
       "sdks/responses/README",