Switch default knowledge collection back to biz (drop+recreate on rebuild),
replace PowerShell rebuild runner with Python, skip README.md imports, and
merge duplicate rag keys in application.yml.
Add confirm-gated rebuild-hybrid endpoint that drops biz_hybrid, clears
api_document and L0, then force-imports knowledge_base markdown into the
dense+BM25 store. Include PowerShell runner and ops README.