Why: squad main (551e11ec) and native main (3a1ad5a) now carry the
nested agent-intent 343b1e6 pins the Dev combination check requires;
the backend nested copies follow.
Evidence: go build ./... green on this combination; trees identical
to the merged library mains.
Impact: none beyond the pins.
Refs: Agent-Squad#27, Agent-Native#23, I2 increment 3 cascade