Why: Q1 WP5 - platform's SQLite becomes an implementation of the
squad Store port so run state and orchestration state live in one
database, and platform's in-process execution goes through the
Executor port instead of bypassing it (X6).
Evidence: all five modules go vet clean and go test ok, including
engine-on-SQLite (state in DB, no run-level JSON files, second
engine recovers from the same DB), SQLiteStore round trip, and the
full squad compatibility net.
Impact: runState/hitlGate exported so the port is implementable;
Options.Store wires into engineDeps; leader persistence and
checkpoints route through the port; PrepareWorkspace no longer
writes run-level JSON (st.save owns it); platform RunInProcess
takes squad.Executor (callers updated); serve mounts the engine on
platform's RunStore - single orchestration.db for both.
Refs: Documents proposal 2026-10-07-agent-stack-n1q1i1-plans.md Q1 WP5
