Why: Q3 WP1/WP2 moved workflow execution out of runtime (workflow_script.go
deleted, so runtime no longer imports internal/tools) into the new
internal/wfcompile package, which legitimately depends on internal/tools
(script host) and internal/workflow (render/validate/Launch data layer).
Evidence: make test-boundaries green after the baseline update (77 edges,
negative test ok); the lint itself flagged both the stale edge and the new
ones (SELF).
Impact: baseline -1 edge (backend/runtime backend/tools), +3 edges
(backend/runtime backend/wfcompile, backend/wfcompile backend/tools,
backend/wfcompile backend/workflow).
Refs: Q3 plan WP1/WP2; task card .task/feature-agent-stack-q3.md