Fix: Correct rag_query parameter mismatch in ask_pancake_enhanced

Fixed TypeError from incorrect parameter passing to rag_query().

Issue:
- ask_pancake_enhanced() called rag_query(query, days_back=days_back, top_k=top_k)
- But rag_query() signature is: rag_query(query_text, top_k, geoid_filter, time_filter)
- rag_query() doesn't accept 'days_back' parameter → TypeError

Fix:
✅ Convert days_back to time_filter parameter
✅ Calculate cutoff timestamp (now - days_back)
✅ Format as SQL filter string: ">= 'TIMESTAMP'"
✅ Pass to rag_query() as time_filter

Code change:
Before:
  results = rag_query(query, days_back=days_back, top_k=top_k)

After:
  cutoff_time = (datetime.utcnow() - timedelta(days=days_back)).isoformat() + 'Z'
  time_filter = f">= '{cutoff_time}'"
  results = rag_query(query, top_k=top_k, time_filter=time_filter)

This properly filters BITEs by timestamp while maintaining the days_back
user-friendly parameter in ask_pancake_enhanced().

Author: sumerjohal