A running spawn's live account is keyed by a node id that is unique per conversation only

[0xKT]

Summary

While a spawned sub-agent runs, its live account (transcript, usage, tool calls) is held in a process-wide index keyed by the node id the model chose for the spawn. That id is unique for one conversation only. Two conversations running a spawn under the same id therefore share one entry.

Steps to reproduce

1. In conversation A, have the model spawn a task with node_id: "step1" on a lane that publishes its transcript (the in-process Raven lane or an ACP agent), long enough to watch.
2. While it runs, in conversation B spawn another task with the same node_id.
3. Open A's task in the desk tasks tab (or read subagent.context for A's step1).

Expected behavior

A's context panel shows A's own run; B's shows B's; each run's live view lasts until that run ends.

Actual behavior

• A's context panel shows B's transcript and, since fix(*): live spawn record, live usage and a leaner node panel subtitle #567, B's live token and tool counts (the later collecting overwrote the entry).
• When A finishes first, its exit drops the shared entry, so B's live view goes blank until B ends.

Where it is decided

• raven/agent/subagent/activity.py: _live: dict[str, RunActivity], one per process, keyed by a plain string.
• raven/agent/subagent/manager.py: activity.collecting(live_key=call_id, ...) with call_id = record.node_id (since a92514e, 2026-09-07, when the spawn record id became the model's own node_id; before that the key was a minted, globally unique call id).
• Readers: raven/rpc/methods/subagent.py (subagent.context) and raven/rpc/methods/tasks.py (tasks.list, since fix(*): live spawn record, live usage and a leaner node panel subtitle #567).
• The dag side does not have this problem: node_live_key(run_id, node_id) carries the run id, and the instance index _live_instances is already keyed by (session_key, agent, handle).

Fix

Key the spawn entry by the record's address (the conversation's node root plus the id), a spawn_live_key(root, node_id) helper beside node_live_key, used by the writer and both readers. No wire change. Fix in #577.