Generate a PayCargo invoice payload for a container.

Always uses the DatabaseStrategy. Branching by charge_type:

• DEMURRAGE: charges filtered by demurrage_end_dt (defaults to POD-local today,
  capped at today + 14 days). Total reflects accrued demurrage through that date.
• DETENTION: requires detention_end_dt (= container's empty_returned_dt for the
  listener path, or today for the daily-cron path). Container must have out-gated
  and live at a detention-enabled (carrier + terminal) pair per cpp_config.
  For credit consignees the invoice total is gnosis_estimated_detention_amount
  with guaranteedType="Blanket Authorization" (informational; outstanding nets
  to zero); for non-credit consignees the total is outstanding_detention_amount
  with haulage-based guaranteedType (PayCargo bills the payer).

Returns:
Invoice data plus details — chargesAvailableThroughDate / demurrageOutstandingAmount
for DEMURRAGE, detentionOutstandingAmount for DETENTION, plus shared fields
(uuid, outGateDt, shipmentNumber).