Land a retailer's own sell-out report against one named account

Import a retailer report for the explicitly named account_id; the account is never inferred. The account declaration and mapping must be confirmed. Reports without a date require week_start (and week_end where appropriate). Unrecognized formats or incomplete declarations are refused. Existing idempotency and account-bound authorization apply to both input sources. Send original CSV/XLSX/XLS bytes inline (up to 8 MiB), or use /files/presigned-url and send application/json with exactly {"s3_key":"organization/user/uploaded-file.csv"} (up to 100 MiB). Uploaded keys must belong to the authenticated organization; foreign keys and URLs are refused. Both sources use the same native retailer parser and preserve its period and provenance. Use confirm_sell_out_declaration to confirm account answers before importing; use preview_sell_out to inspect the same file without writing. not_matched.by_reason counts every row by resolver outcome, including matches; not_matched.total counts refused rows, and not_matched.by_reason_words explains each outcome. Repeated files report both rows submitted and rows actually changed. Requires Tightly Connect; unavailable plans return 403 plan_excludes.

Scope: sell_out:write, which includes sell_out:read.