docs(heartbeat): plan approval routing follow-up

[artemgetmann]

Review Fast Path

• User path fixed: follow-up plan for heartbeat approvals after PR fix(heartbeat): relay approval receipts to source topics #1021 foundation landed.
• Proof: npx -y pnpm@10.23.0 check:docs; git diff --check origin/main...HEAD.
• Shared-state footgun removed: runtime deploy stays explicitly separate; plan keeps feature work out of shared main runtime until after merge and approval.
• Still hurts: implementation is not in this PR; pending approval storage and mirror-only routing still need code.

Why This Matters

• PR fix(heartbeat): relay approval receipts to source topics #1021 added source-topic receipt plumbing, but the final UX should not rely on model reconstruction or noisy visible topic posts.
• The plan pins the next slice: exact stored drafts, mirror-only checkpoints by default, and visible source-topic relay only when the task needs to act.

Scope Boundary

• Adds a short-lived Jarvis follow-up plan.
• Links it from the Jarvis docs map.
• Does not change runtime behavior.
• Does not deploy or restart Jarvis.

Verification

• npx -y pnpm@10.23.0 check:docs
• git diff --check origin/main...HEAD

AI Assistance

• AI-assisted
• Testing degree: targeted