[aaqilniz]

• Implements the jsonContains operator mapping inside PostgreSQL's buildExpression to support array/containment queries (such as those required for referencesMany relations).
• Automatically parses and normalizes stringified JSON or single values into an array, generating PostgreSQL-native containment checks (col @> CAST(? AS JSONB)) connected with OR.
• Adds comprehensive unit and integration tests covering record filtering and raw SQL string/parameter generation for JSONB fields.

This PR depends on PR #11883 (loopbackio/loopback-next#11883) to successfully access property metadata after relation creation.

Checklist

• DCO (Developer Certificate of Origin) signed in all commits
• npm test passes on your machine
• New tests added or existing tests modified to cover all changes
• Code conforms with the style guide
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