feat(therapy): drop card bytes as the commit parses them

[mr-blithe]

An import was uploaded to be read once, but pap_file kept every byte of the
card after the commit had written the parsed night, and nothing has read a
byte back since: the panel, the export, the share and the admin read model
all go through pap_day, pap_event and pap_channel.

The opening slice now deletes every file left without a day, which covers the
card level files it just parsed into the import, the ones whose night was
replaced and the ones no date could be read from, and fillDay deletes a
night's files in the transaction that stores the night. Transactional so a
slice that rolls back keeps them and the client's retry still finds a night it
can parse. A night that would not parse takes its files with it either way,
through the dropped row's cascade or explicitly when the card's own summary is
kept.

The table stays: it is where a chunked upload lands and where the commit reads
from. What it no longer is, is an archive, so a parser fix can only be replayed
over a card uploaded again.

Co-Authored-By: Claude noreply@anthropic.com