fix(mirror): correct docstring - writes SQLite only, not JSONL

[HeLLGURD]

Bug

mirror_to_session() in gateway/mirror.py documents:

Finds the gateway session that matches the given platform + chat_id,
then writes a mirror entry to both the JSONL transcript and SQLite DB.

But the implementation only calls _append_to_sqlite(session_id, mirror_msg) -
there is no JSONL write. The docstring promises a write path that does not
exist, which misleads anyone reading or debugging the mirror flow into looking
for a JSONL transcript that never gets written.

This is intentional behavior - sessions are stored in SQLite
(SessionDB / hermes_state.py), and the per-session transcript.jsonl is a
legacy format that the codebase only cleans up, never writes here. So the
code is correct and the docstring is wrong.

Fix

Update the docstring to describe what the function actually does:

Finds the gateway session that matches the given platform + chat_id,
then writes a mirror entry to the SQLite session database.

Docstring-only change; no behavior change. The SQLite-only write path is left
exactly as-is.

[teknium1]

Thanks for the precise documentation correction. Current main still makes the inaccurate dual-store claim at gateway/mirror.py:38, while the actual persistence path calls only _append_to_sqlite() at gateway/mirror.py:79; that helper writes through SessionDB.append_message() at gateway/mirror.py:191-201. The proposed one-line change accurately describes that behavior, and existing coverage already asserts the SQLite writer is called (tests/gateway/test_mirror.py:166-179).

Automated hermes-sweeper review.

[teknium1]

Docstring already reads "Append a delivery-mirror message to the target session's SQLite transcript" on current main (gateway/mirror.py::mirror_to_session), so this landed independently. Thanks @HeLLGURD — your #48483 preview fix went in via #109134.