Data flow reporting is built in, gated by tengu_pewter_grebe and an organization policy

What

This release adds data flow reporting, a new kind of record Claude Code can keep in a session. The members did not trace what the records contain or where they are sent.

• Gate: it works only when the switch tengu_pewter_grebe is true and the organization policy allows allow_data_flow. The switch falls back to false when the server sends no value. Nothing has been read about it.
• Policy: allow_data_flow is a new organization policy entry labelled "Data flow reporting", with requirement ID HIPAA-R150. It is denied under hipaa and zdr (zero data retention), and if the policy is not cached or the check fails open, it also resolves to deny.
• Transcript: the session file gains data-flow-records, data-flow-incomplete and derived-from entries. The first two add up over the session and the last one keeps only the latest value. For agents they are written at exit, a helper decides whether they are written, and the session file reader understands the "snapshots" kind.
• Session state: the saved state now carries dataFlowRecords, dataFlowOwed, dataFlowIncomplete and dataFlowDerivedFrom.
• Forks: forking a conversation copies the data-flow records, the incomplete flag and the derived-from lineage into the new session.
• Tombstone removal: removing deleted entries from a session file now refuses to edit a file that ends before its reported size.

Why

Session files can now hold a new record type that follows a conversation into its forks. Organizations under HIPAA or zero data retention are denied it by policy, and nothing turns it on unless the server sends a value for its switch.