The conversation view, live stream and show read Session traces #987

Parent

#700

What to build

The Console and show read a session from its Session trace when it has one.

• The conversation view renders the log records. It unwraps each record's raw event and keeps today's Claude and Codex rendering. All six Harnesses in the conversation view #990 grows it to all six Harnesses.
• The live view streams the log records' file by byte offset. A reconnect resumes where it left off, as it does for Session logs.
• show and show --json report the latest record of the live session's Session trace.
• Silent and the heartbeat watch the log records' file grow. Their rules don't change.
• A session with only an old Session log still renders as it does today.

Acceptance criteria

• The Console's route tests, given Claude and Codex Session-trace fixtures, render the same conversation as the matching Session-log fixtures.
• Browser tests: a live session appends from its log records without redrawing, and a reconnect resumes by byte offset.
• show --json's latest event comes from the latest record.
• Silent and the heartbeat react to the log records' file growing.
• Old Session logs still render, stream and show as before.