Metering telemetry is journaled at ~10 Hz during active turns, so marathon
reasoning runs balloon the durable run journal (12.4 MB of a single 18 MB run
was metering). On a mid-run refresh the reconnect path replays the entire
journal as one unpaced SSE burst, OOM-crashing the browser tab in a
crash-refresh loop while the server stays healthy.
- Write time: RunJournalWriter.append_sse_event() skips metering rows via
REPLAY_SKIPPED_SSE_EVENTS, returning None so caller journal-id plumbing is
untouched and remaining journaled seqs stay contiguous.
- Replay time: _replay_run_journal() and emit_replay() filter metering rows
through journal_replay_visible(), so legacy journals never stream the
backlog either.
- Readers (read_run_events / read_session_run_events) deliberately keep every
row: cursor math and the offline-gap coverage check count seqs.
Refs #7272
laitekin