What
When session state is carried forward into a fork or resume, a new helper now strips it of certain state so it doesn't leak into the new session. It clears artifactCommentMonitor and artifactAutoReactLedger unconditionally, along with a full set of bridge-related fields: bridgeSessionId, bridgeLastSeq, bridgeDialogKinds, bridgeSessionGroupingId, bridgeNoHistoryBackfill, bridgeOwnerAccountUuid, and bridgeOwnerOrganizationUuid. It can also optionally strip worktreeSession and relocatedCwd.
Why
This prevents a forked or resumed session from inheriting artifact-monitoring or bridge-connection identifiers that belonged to the original session, avoiding cross-session state confusion.