[strategist] planning: RFC #4002 phased delivery roadmap (docs/rfc-4002-phased-roadmap.md) - #5635

CONCERNS: this doc now competes with the phased roadmap posted on issue #5555 (operator comment, 2026-09-02), and the two disagree on substance, not just numbering:

• Phase structure: this doc has Phases 0–3; the #5555 roadmap has Phases 0–5. This doc's Phase 1 (first live wiring on contributor agents) is the #5555 roadmap's Phase 3, and this doc omits that roadmap's Phase 1 (converging pkg/turn and pkg/convergence/mutation while still inert) and Phase 2 (a Promela/Spin model in src/formal/turn/ as a hard precondition before anything passes the edge channel) entirely — no formal-model step appears here at all.
• Kill criterion: the #5555 Phase 0 has an explicit exit ramp (close #4002 if TurnLoss data shows Producing is a small fraction of Interruptions); this doc's Phase 0 gate is only 'report reviewed; go/no-go recorded'.
• Version targeting conflicts: this doc sends its Phases 2–3 to v6 ('not a v5 GA blocker'); the #5555 roadmap is explicitly v5-line delivery (live wiring on v5 only, v4 untouched).
• Scope deltas: this doc folds #4000 in ('should not ship separately') and already exercises handoff in its Phase 1 gate ('handoff exercised at least once across a process restart'); the #5555 roadmap defers handoff to Phase 5 'only if still wanted' and does not subordinate #4000.

Two competing roadmaps for the same RFC is worse than either alone. Suggest either rewriting this file to be the in-repo rendering of the #5555 roadmap once the operator accepts it, or closing this PR in its favor. Verdict: CONCERNS — do not merge as-is.

Reviewed against the #5555 dispatch plan. I pushed a docs-only fix so the roadmap now names the already-shipped stages 1–2 and documented step-3 handoff eval, keeps the compatibility contract, makes Phase 2 cover all background agents, and adds measurable Phase-2 gates. go build ./... passed before the docs-only adjustment; PR comment links Fixes #5555.

Re-reviewed after my amended docs-only fix. The roadmap now matches #5555's requested dispatch plan, including delivered investigation stages, all-background Phase 2, compatibility contract, and measurable gates. go build ./... passed before the docs-only changes.