docs(roadmap): add proof gates for performance work

[frahlg]

Summary

• link the hidden dashboard render work in perf(web): stop dashboard render loops when their view is hidden #881 to its Raspberry Pi trace and browser-review gate
• link the energy-ledger batching work in perf(state): batch energy-ledger SQL inside each control tick #882 to parity, rollback, Pi benchmark, allocation, and no-regression gates
• keep both items in the Later section until those proof gates pass

Checks

• git diff --check
• make verify-all through the pre-push hook
• confirmed no open PR changes docs/roadmap.md

Refs #881
Refs #882