feat(qdrant): Add filtering system for Qdrant vector searches

[Shinu95J]

Add type-safe filtering system

Summary

Adds a comprehensive, type-safe filtering system for Qdrant vector searches with support for multiple condition types and logical clauses.

Filter Conditions

Type	Description	SQL Equivalent
TextCondition	Exact string match	WHERE city = 'London'
BoolCondition	Boolean match	WHERE active = true
IntCondition	Integer match	WHERE priority = 1
TextAnyCondition	Match any of values	WHERE city IN ('London', 'Berlin')
IntAnyCondition	Match any of integers	WHERE priority IN (1, 2, 3)
TextExceptCondition	Exclude values	WHERE city NOT IN ('Paris')
IntExceptCondition	Exclude integers	WHERE priority NOT IN (0)
TimeRangeCondition	Datetime range	WHERE created_at >= '2024-01-01'
NumericRangeCondition	Numeric range (float)	WHERE price >= 100 AND price <= 500
IsNullCondition	Check if field is null	WHERE deleted_at IS NULL
IsEmptyCondition	Check if field is empty/missing	WHERE tags IS EMPTY

Logical Clauses

Clause	Logic	JSON Key	Description
Must	AND	must	All conditions must match
Should	OR	should	At least one condition must match
MustNot	NOT	mustNot	None of the conditions should match

Field Type Separation

Field Type	Storage Location	Example
InternalField	Payload top-level	search_store_id
UserField	Under custom. prefix	custom.document_id

JSON Serialization

Condition Field	JSON Key
Key	field
Value (match)	equalTo
Values (any)	anyOf
Values (except)	noneOf
TimeRange.Gt	after
TimeRange.Gte	atOrAfter
TimeRange.Lt	before
TimeRange.Lte	atOrBefore
NumericRange.Gt	greaterThan
NumericRange.Gte	greaterThanOrEqualTo
NumericRange.Lt	lessThan
NumericRange.Lte	lessThanOrEqualTo

Usage

filters := &FilterSet{
    Must: &ConditionSet{
        Conditions: []FilterCondition{
            TextCondition{Key: "search_store_id", Value: "store-123"},
            TextAnyCondition{Key: "city", Values: []string{"London", "Berlin"}},
            TimeRangeCondition{
                Key:   "created_at",
                Value: TimeRange{Gte: &startTime, Lt: &endTime},
            },
            NumericRangeCondition{
                Key:       "price",
                Value:     NumericRange{Gte: &minPrice, Lte: &maxPrice},
                FieldType: UserField,
            },
        },
    },
    MustNot: &ConditionSet{
        Conditions: []FilterCondition{
            BoolCondition{Key: "deleted", Value: true},
            IsEmptyCondition{Key: "tags"},
        },
    },
}

JSON Output Example

{
  "must": [
    {"field": "search_store_id", "equalTo": "store-123"},
    {"field": "city", "anyOf": ["London", "Berlin"]},
    {"field": "created_at", "atOrAfter": "2024-01-01T00:00:00Z", "before": "2024-12-31T00:00:00Z"},
    {"field": "price", "greaterThanOrEqualTo": 100, "lessThanOrEqualTo": 500}
  ],
  "mustNot": [
    {"field": "deleted", "equalTo": true},
    {"field": "tags"}
  ]
}

Payload Helper

payload := BuildPayload(
    map[string]any{"search_store_id": "store-123"},  // Internal (top-level)
    map[string]any{"document_id": "doc-456"},        // User → custom.document_id
)