Incoming dataset

Copy the challenge dataset to this directory as challenge_data.csv.gz before running the future importer. The archive is intentionally ignored by Git.

The server-side Docker/bootstrap contract is documented in docs/IMPORT-WORKFLOW-SPEC.md. During deployment implementation, the operator places the same filename under the deployment repository's Git-ignored data/incoming/ directory; the first-start Bash script mounts it read-only into the one-shot importer container.

Expected source columns:

session_key, try_seq, terminal_key, merchant_key, category_id,
category_title, amount, adjusted_fee, session_status, try_status,
switch_response_code, psp_code, issuer_bank_code, payer_card_key,
verify_type, init_time_ms, verify_time_ms, created_at, try_created_at,
verified_at, settled_at, expire_in

Do not add merchant passwords or other secrets to this directory. Demo credentials will be generated/seeding inputs managed separately through secure environment or one-off administrative workflows.

The source contains session markers where try_seq = 0 and try_status = NoAttempt. The importer must create the session but no normalized payment-attempt row for these records.