Add module-level logger to serp_api.py with INFO-level messages for
patent queries and PDF downloads, and DEBUG-level messages for cache
hits and parsing details. All three target files (analyzer.py,
serp_api.py, llm.py) now use structured logging with no print() calls.
Closesleeworks-agents/SPARC#46
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>