Add production-scale sorting support with orderBy/order parameters:
- Sort by any field including createdAt, updatedAt, timestamps
- Works in both metadata-only and vector+metadata query paths
- O(k) memory complexity where k = filtered results
Fix timestamp sorting precision issue:
- Load actual timestamp values from entity metadata for sorting
- Avoids 1-minute bucketing precision loss
- Maintains bucketing for efficient range queries
Fix range query operators:
- Normalize min/max bounds before comparison with bucketed index
- Ensures gte, lte, gt, lt work correctly with timestamps
Standardize operator syntax:
- Canonical: eq, ne, gt, gte, lt, lte, in, between, contains, exists
- Deprecate: is, isNot, greaterEqual, lessEqual (remove in v5.0.0)
- Maintain backward compatibility with aliases
Test results: All sorting and range query tests pass, no regressions