For large CSVs (e.g. the 34k-row ARRL dump), the synchronous commit
path blocked for minutes and a crash mid-commit left no audit trail.
Refactor to run inserts + enrichment enqueues via Oban.
- New import_runs table: stores preview rows + running counters (total,
processed, imported, refined, error) + status + errors map + timing.
- New :contact_import Oban queue (limit 4) + ContactImportWorker.
Args: {import_run_id, offset, limit}. Each chunk (100 rows) inserts
its slice via CsvImport.commit_rows/1, atomically increments counters
in one update_all, flips status, and broadcasts progress on
'csv_import:<id>' PubSub topic.
- CsvImport.commit_rows/1 extracted from commit/1 (back-compat preserved).
New CsvImport.enqueue/2 persists the run + dispatches N chunk jobs.
Also: submit page copy updated from '902 MHz and up' to '50 MHz and up'
matching the band allowlist expansion done earlier.
LiveView UI for /imports/:id is a separate commit.
Graham McIntire
48833f15be