Usage: rebar import [--dry-run] [file]

Import tickets from export NDJSON for a clean rebar-to-rebar migration.

positional arguments:
  file       NDJSON file to import (stdin if omitted)

options:
  --dry-run  report without writing

Ticket creation, parent assignment, file impact, verification commands, and
comments are committed in batches of up to 256 events. Links and status changes
are committed one event at a time. Rebar defers the push until import work
finishes successfully. Each run scans stored source_id values and skips matching
records, so a serial rerun does not duplicate tickets created by an earlier run.
The import does not provide whole-file atomicity. A crash between passes can
leave incomplete tickets. A serial rerun skips those tickets based on source_id
and does not complete the missing events automatically. Run imports serially.
Concurrent imports can scan before either run records a source_id and can create
duplicate tickets.
