test(styles): guard renderer style selector inventory

[jackwener]

Summary

• add a renderer style selector inventory contract that fails on unaccounted orphan class selectors
• document the runtime-only selector allowlist for OverlayScrollbars and dynamic provider status classes
• remove the final stale .modePill renderer style hook after PR chore(css): drop 2 more verified-dead selectors (.providerCatalog, .connectionStatus) #255

Verification

• npm --workspace @maka/ui run build
• npm -w @maka/desktop run typecheck
• npm -w @maka/desktop run build
• node --test dist/main/tests/renderer-style-pruning-contract.test.js
• git diff --check