/simplify-code review found _notify_single_query_session_finalize was
missing the _handed_off_session_ids guard that _should_emit_cleanup_session_finalize
and _emit_interrupted_session_end already had. One-shot CLI queries that
somehow handed off would still finalize the session via this path.
Added guard + test.
Two data-loss bugs reported by users:
1. /handoff CLI→gateway race (#88234): After /handoff completed, CLI
cleanup called finalize_session on the session the gateway just
reopened. This set end_reason on a row the gateway was actively
writing to, causing the handoff leg to vanish from session history
and breaking session_search recall. Fix: add _handed_off_session_ids
module-level set (mirrors _single_query_finalize_attempted_session_ids
pattern). _handle_handoff_command registers the session_id on
completion; _should_emit_cleanup_session_finalize and
_emit_interrupted_session_end check it before firing.
2. state.db corruption silent failure (#88235): When SessionDB init
failed at gateway startup, the error stayed in logs — messages
flowed but nothing was persisted, with no user-visible indication.
Fix: store _session_db_init_error on GatewayRunner, broadcast a
recovery-guidance message to all home channels via
_send_session_db_warning_notifications() after the gateway connects.
Also improved the 'corrupt' persistence cause wording in
_format_turn_completion_explanation to include the full recovery
path (hermes doctor --fix, sqlite3 .recover, backups).
Tests: 6 new tests for handoff cleanup race, 3 for corruption wording.
All existing CLI/turn-completion tests pass.
kshitij