Searching "JOHN" or "ord-1001" returned no orders because SQLite instr()
is case-sensitive. Compare lowercased values for order number, customer
name, and email. Adds API regression tests for both cases.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HUfxyr6EcRi4EYSX1wLoRh
