chore(deps): add renovate.json

Author: khepri-bot[bot]

renovate.json

@@ -0,0 +1,6 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "description": [
+    "Managed by khepri-deps/renovate — global config provides weekly Monday schedule, 14-day release cooldown, and vulnerability alert bypass."
+  ]
+}