Prevent geographic false positives in cache lookups. Queries like
"musea in Amsterdam" vs "musea in Noord-Holland" have ~93%
embedding similarity but completely different answers.
Changes:
- Add ExtractedEntities interface for structured cache keys
- Implement fast entity extraction (<5ms, no LLM) with regex patterns
- Extract institution types (GLAMORCUBESFIXPHDNT), locations, and intent
- Generate structured cache keys (e.g., "count:M:amsterdam")
- Raise similarity threshold from 0.85 to 0.97 to match backend DSPy
- Add 'structured' match method to CacheLookupResult
The entity extractor recognizes:
- 19 institution types (Dutch + English patterns)
- 12 Dutch provinces with ISO 3166-2:NL codes
- Major Dutch cities with settlement codes
- Query intents (count, list, info)
This ensures geographic queries get different cache entries even when
embeddings are highly similar.
