The Qdrant vector store's _create_filter only handled simple equality
and a single gte+lte range case, causing ValidationError for all other
operators documented at docs.mem0.ai/open-source/features/metadata-filtering.
Add _build_field_condition to translate the universal filter syntax into
Qdrant-native models:
- Comparison: eq, ne, gt, gte, lt, lte → MatchValue / MatchExcept / Range
- List: in, nin → MatchAny / MatchExcept
- String: contains, icontains → MatchText
- Logical: AND, OR, NOT → Filter(must/should/must_not), recursive
Existing simple equality and gte+lte range filters continue to work
unchanged (backward compatible).
Closes#3975
Longwei Liu
7e0968bbc8