Submit dispute evidence and finalize a dispute via the Braintree GraphQL API before the reply-by deadline

Steps

1. Query the Dispute node to confirm its status is OPEN and read its replyByDate before attempting to add evidence — only OPEN disputes accept new evidence
2. For text-based evidence (a refund transaction ID, tracking number, etc.), call the createDisputeTextEvidence mutation with the disputeId and the evidence content
3. For file-based evidence, call createDisputeFileEvidence using Braintree's partial implementation of the GraphQL multipart request spec: send a multipart/form-data request with an operations part (the query/variables JSON, containing a "file": null placeholder), a map part linking that placeholder to the file field, and the file itself as PNG, JPG, JPEG, or PDF under 4 MB
4. Once all evidence is attached, call the finalizeDispute mutation with the disputeId to submit the case for review
5. Submit before the dispute's replyByDate — missing it isn't a soft failure: Braintree automatically sends an Accept response on your behalf and you lose the ability to contest the dispute