A session renamed with /rename should rename its loop #261

Is your feature request related to a problem?

Renaming a Claude Code session from inside it (/rename hello) changes the session's name, but the loop's card in GraphCode keeps whatever title it was created with. The two names then disagree, and the sidebar keeps showing a name the human has already replaced.

The loop title is the one field a human is expected to change after the fact — it's written before the work exists, and what the loop turns out to be doing is only known once it's running. /rename is a human saying exactly that, in the session, and GraphCode ignores it.

Describe the solution you'd like

When a session's title changes, rename the node to match.

Claude Code writes an explicit record to the transcript GraphCode already tails:

{"type":"custom-title","customTitle":"hello","sessionId":"a825abc7-..."}

This is written only by /rename, so it is an unambiguous statement of human intent — distinct from the agent-name record, which carries an auto-assigned name (angleReuse2) and appears in sessions nobody renamed. Only custom-title should be read.

Scope

• Session → loop only. An app-side rename should not be pushed back into the session, and must not be clobbered by the next poll.
• Claude Code only. The other three backends have no equivalent record; they should report nothing rather than a guess.

Additional context

The plumbing already exists: GraphCommand.renameNode, ClaudeSessionLog.transcript(forSessionID:), and the 15s pollPresence tick that already opens the same file for the summary rail.