fix(run-journal): skip metering telemetry on write and replay (#7272)

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

api/routes.py

@@ -10710,6 +10710,7 @@ from api.run_journal import (
     _parse_run_journal_event_id as _shared_parse_run_journal_event_id,
     bound_run_journal_snapshot_args,
     find_run_summary,
+    journal_replay_visible,
     read_run_events,
     read_session_run_events,
     session_journal_fingerprint,
@@ -18575,6 +18576,8 @@ def _replay_run_journal(
         max_seq=max_seq,
     )
     for entry in journal.get("events") or []:
+        if not journal_replay_visible(entry):
+            continue
         _sse_with_id(
             handler,
             entry.get("event") or entry.get("type") or "message",
@@ -19110,6 +19113,8 @@ def _handle_session_run_journal_stream_for_session(handler, parsed, session_id):
 
     def emit_replay(events, stream_id, cutoff_seq):
         for entry in events:
+            if not journal_replay_visible(entry):
+                continue
             event_id = str(entry.get("event_id") or "")
             event_seq = _run_journal_same_run_seq(event_id, stream_id)
             if cutoff_seq is not None and event_seq is not None and event_seq > cutoff_seq: