Create or update many companies at once, matched by companyId (the dashboard's CSV importer). Body:
{ companies: [{ companyId, name, plan, domain, value, sla, tags, address, customData, ownerEmail }] },
at most 1000 rows per call. Each row is written like PUT /companies/{companyId}; rows sharing a
companyId are collapsed (the last one wins) and lastSeenAt is not touched. Answers how many were
imported, the positions of rows without a companyId, and the companies that failed. Re-sending rows
is safe.
Bearer <token>.Ok
Companies whose write failed; re-sending them is safe.
Positions (0-based) of rows without a usable companyId; nothing was written for them.
Companies created or updated.