Why: check-pins requires nested and Dev-level pins to agree; squad main
advanced to 819b0c5 (nested agent-native pin #48) and backend main to
fe7c245 (nested agent-squad pin #103) after the Q3 WP1-WP5 merges.
Evidence: both component PRs CI green (GATE); make test recorded via
make evidence in the follow-up commit on this branch.
Impact: deps/agent-squad 663e89e -> 819b0c5; modules/backend 4791b2e ->
fe7c245; deps/agent-native stays 37c5e6f.
Refs: Q3 plan WP6; task card .task/feature-agent-stack-q3.md