Step 1.1 of the S3b phase 1 plan. Wiring only: the approval gate for asset
targets is not enforced yet and no behaviour changes.
- Planner.Plan and MainAgent.Chat take a hooks parameter, like Worker.Execute.
Their sessions had no hooks, so nothing saw their tool calls before execution.
- guard.NewTargetOnly: the guard for those two agent kinds. It runs the
target-gate seam only: no intercept rule, no fallback judge, and no entry in
the audit ring (Guard.record is untouched and not called for these calls).
- Task.TargetGuard, built beside Task.Guard.
- intercept.WithTargetScope / TargetScopeFromContext: task id or conversation
id, an Enabled func and a wait bound, set at the five session entry points
(planner round, final planner round with wait bound 0, main-agent turn,
worker intent, conversation turn).
The seam allows every call and reads and writes nothing. No task or
conversation has an opt-in flag yet, so Enabled is nil (off) everywhere.