Fix Metadata Filtering

[abdeliibrahim]

    // TODO: IN operator doesn't work with Supabase, so we'll use EQ operator for now
    // const retriever = index.asRetriever({
    //   similarityTopK: 5,
    //   filters: {
    //     filters: [
    //       {
    //         key: "source_document",
    //         operator: FilterOperator.IN,
    //         value: documents,
    //       },
    //     ],
    //   },
    // });
    //
    // Create a custom retriever that handles multiple documents with EQ operator