Summary

• split maker discovery peer counts into memoized selectors
• avoid building the full peer table data until the peer details dialog is open
• keep the existing connected-peer history and dialog behavior intact

Part of #727.

Validation

• git diff --check
• COREPACK_HOME=/private/tmp/codex-corepack-cache YARN_GLOBAL_FOLDER=/private/tmp/codex-yarn-global YARN_CACHE_FOLDER=/private/tmp/codex-yarn-cache corepack yarn eslint src/store/selectors.ts src/renderer/components/pages/swap/swap/init/deposit_and_choose_offer/MakerDiscoveryStatus.tsx --quiet
• corepack yarn tsc --noEmit (blocked: src/models/tauriModel.ts is not generated in this checkout)