List accessible documents with metadata filtering.
Supported operators: $and, $or, $nor, $not, $eq, $ne, $gt, $gte, $lt, $lte,
$in, $nin, $exists, $type, $regex, $contains.
Implicit equality (backwards compatible):
{"status": "active"}
Uses JSONB containment, matches scalars inside arrays, JSON-serializable types only.
Explicit operators (typed comparisons):
{"priority": {"$eq": 42}, "created_date": {"$gte": "2024-01-01T00:00:00Z"}}
Supports typed metadata (number, decimal, datetime, date) with safe casting.