feat: enforce strict lookup consistency checks (#1046)

Fail mixed name+identifier lookup when resolved records disagree instead of returning a union.

This makes lookup strict by title, keeps identifier-backed enrichment authoritative, and adds regression tests for mismatch and exact-only behavior.

Co-authored-by: florath-ai-assistant[bot] <Andreas.Florath@telekom.de>

Author: coding-ai-assistant[bot]