PolicyService.route now auto-runs config_mutation and reversible_low when
sessionID is empty (dsh sidecar path), routing as 'dsh-gate'. Destructive
still queues. This eliminates the two-layer consent issue: dsh pre-execute
is the sole consent gate, oikos no longer queues dsh-originated mutations.
Also updates the dsh plan with Phase 1-3 completion status and the
architectural decision that _session_id injection is permanently deferred.
v0.38.0