Add the Relay method skill (execute a long plan as a chain of independent
sessions handing off via spawn_session) under a top-level skills/ folder that
follows the open agent-skills convention, installable with the skills CLI.
Also clarify the changeset-changelog skill: no changeset is needed for changes
outside the npm release allowlist (package.json files), such as repo-only
agent skills under .agents/ and skills/.
Add spawn_subsession / list_subsessions / read_subsession tools that let an
agent start child sessions it stays attached to: the child records its parent
in the session tree, the parent is notified (as a system-authored custom
message that wakes an idle parent and queues behind in-flight work) when the
child stops working, and the parent can inspect children's status and result.
Gated behind a beta flag, off by default, mirroring spawnSessions: enable via
PI_WEB_SUBSESSIONS, the subsessions config key, or the Settings toggle. Also
requires spawnSessions.
Also fix the release skill so the version step resyncs package-lock.json
(npm install --package-lock-only) and the commit step refuses a release where
package.json and package-lock.json versions disagree.
Federico Jaramillo Martinez