session.save wrote the in-memory history, so turns in-place compaction archived were missing from the
snapshot and sessions.max_export_messages never applied, unlike CLI and messaging /save json since the
#130339 fix. The two existing call sites' cap check + export + undone-row filter move into
hermes_cli.session_export.load_save_snapshot; the CLI, the messaging gateway (one off-loop hop) and the
tui_gateway handler all call it. The TUI handler reads the session's own profile db under that profile's
config, refuses an oversized session with rpc error 4131 (the same message as the CLI), and keeps the
in-memory export as the fallback when no stored row exists. Turn-isolated sessions run the same handler on
the compute host; the host now forwards the handler's error code so the refusal arrives as 4131, not 5011.
Refs #130339
b564815995