core/operations: generalize kind-check validation to reviewOperation and reproduceOperation

[windoliver]

Summary

updatePlanOperation validates that previous.kind === 'plan' before creating a derives_from relation (src/core/operations/plan.ts:117, added by Issue 6A in #228). The same class of bug exists in reviewOperation and reproduceOperation: they accept any CID as a target without verifying the kind matches the relation type.

Specifically:

• reviewOperation accepts targetCid: string but doesn't check that the target is reviewable (typically kind: 'work'). You can review a discussion or a plan today.
• reproduceOperation accepts targetCid: string but doesn't check that the target is reproducible (typically kind: 'work' with artifacts). You can reproduceOperation against a chat message.

Both produce a relation that points at a contribution of the wrong kind, polluting the DAG.

Recommended fix

Two options:

A. Mirror the pattern from updatePlanOperation — add explicit kind checks in each operation:

// In reviewOperation
if (target.kind !== 'work') {
  return validationErr(``Cannot review a '${target.kind}' contribution`);
}

Effort: ~30 min for both operations + tests.

B. Generalize validateRelations to accept an expected-kind map:

// In contributeOperation
await validateRelations(store, relations, {
  expectedKinds: {
    derives_from: ['plan'],
    reviews: ['work'],
    reproduces: ['work'],
  },
});

Effort: ~2h. Centralizes the rule but touches more files.

Recommended option

Start with A (per-operation checks) — it's less code, mirrors the existing updatePlanOperation pattern, and is sufficient unless we add more relation types where this would matter. Move to B if/when a third operation needs the same validation.

Context

Surfaced during the #228 review (Issue 6 generalization, deferred per the locked-in plan: "Plan only this PR, file follow-up for review/reproduce"). The plan-only fix landed in commit 5ccf818.

References

• src/core/operations/plan.ts:117-122 — the kind-check pattern in updatePlanOperation
• src/core/operations/contribute.ts:546-580 — reviewOperation
• src/core/operations/contribute.ts:586-624 — reproduceOperation
• protocol: plan/message operations bypass policy enforcement and topology routing #228 — parent review