Move orchestration out of the route handlers into a service layer

Housekeeping: lint in CI, client lifecycle, and a truer breaker signal

Test the search URLs, and delete the harness that hid them

Add a circuit breaker to the multi-backend search fallback (item from review)

Run the container as a non-root user (item from review: Dockerfile hardening)

Validate patent_id shape before hitting Google Patents/OPS

Deduplicate app.py's search endpoints (item 4 from review)