feat: polish DM surfaces and fix dev runtime

[AzureFoxStudios]

Summary

• Restores the audited DM visual polish baseline on a fresh branch from updated main
• Polishes DM list/thread surfaces, controls, focus states, active/pinned/empty states, composer, message bubbles, and action buttons
• Fixes the dev-server runtime import for the CommonJS opus-recorder package
• Cleans malformed nested CSS variable fallbacks that caused esbuild CSS syntax warnings during production build

Verification

• bun run check: 0 errors, 53 existing warnings
• STATIC_BUILD=1 bun run build: passed
• Dev server reached HTTP 200 after fixing opus-recorder import
• Headless Chromium guest login smoke reached the app shell
• Browser tool itself is still broken in this Hermes session, so full DM visual screenshot coverage was limited; with no backend/users, the runtime showed the quick DM empty state rather than populated DM threads

Notes

• Preserved the previous dirty tree in stash@{0} and /var/home/Ronin/wabi-backups/pre-main-update-20260602-140424.tar.gz before this branch work