Telegram's deliverReplies dispatches via Grammy SDK directly, bypassing
deliverOutboundPayloads where the channel-mirror writer runs. Outbound
assistant replies were never appended to the session transcript, leaving
Telegram .jsonl files empty (the sessions.json sessionFile path was
populated but the file was never created on disk).
Add an optional transcriptMirror callback param to deliverReplies and
populate it from bot-message-dispatch's deliveryBaseOptions. Reuses the
existing appendAssistantMessageToSessionTranscript helper that
deliverOutboundPayloads already calls. Also mirrors preview-finalized
replies so the transcript captures all final assistant output.
Plugin SDK boundary expansion: re-export
appendAssistantMessageToSessionTranscript from
plugin-sdk/agent-harness-runtime so extension code can call it without
reaching into core src/. API baseline regenerated.
Addresses openclaw#75991 for telegram + CLI runtime combinations.
Supersedes openclaw#77484 (incorporates reviewer feedback: preview-
finalized mirror + changelog entry).
