fix(claude): show the same three rows around a compaction, live and reopened

A `/compact` produced two different pictures. Live: the prompt the user
typed, then the divider. Reopened: the divider, then the continuation
summary. Each view was missing exactly what the other had.

The prompt was missing from history because a client-side slash command
drives no model turn, so `pending_command_verdict` drops it — right for
`/model`, wrong for the one command that leaves a mark of its own. It
can't simply be emitted where the CLI wrote it, either: the
local-command echo is written when the command FINISHES, so the record
order is boundary, continuation summary, `<command-name>/compact`, and
keeping file order prints the request below its own answer. The parser
now holds the divider's index open and inserts the prompt there, which
also keeps `/compact <instructions>` intact. Measured on a 19,435-line
transcript that a resume replayed six times over: 7 dividers, 7 prompts.

The summary was missing live because the persisted-tail strip removes
everything after the last persisted user turn — correct for the reply
being streamed, which the live stream re-shows, but a `system` turn has
no live counterpart at all. Claude writes the continuation summary as
one, and an AUTOMATIC compaction lands it mid-turn, so it stayed hidden
for the whole rest of the turn and then appeared out of nowhere on
reopen. System turns now survive the strip.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>