Fix malformed entity lookup retry loop

[paco-ravenpack]

Summary

• Skip malformed Knowledge Graph entity lookup results during search post-processing
• Prevent infinite retry loops when one entity in a lookup batch lacks required SDK fields
• Bump package version to 1.1.2 and add changelog entry

Test plan

• uv run pytest tests/test_search
• uv run --extra azure --extra bedrock --extra openai pytest
• uv run --with ruff ruff check src/bigdata_research_tools/search/search_utils.py tests/test_search/test_search_utils.py
• Smoke-tested Risk Analyzer watchlist path with patched local BRT