fix: restore floating voice HUD

[DHLbigmonster]

Summary

• align react-dom with react to prevent the floating HUD renderer crash
• make the floating HUD use a visible fallback background and capsule
• add renderer load/crash/console logging for the floating window
• show the HUD immediately when voice state becomes non-idle

Verification

• node --experimental-strip-types --check src/main/windows/floating.ts
• pnpm -s typecheck
• pnpm -s test
• pnpm run install:app
• installed app log shows the new startup has Floating window renderer loaded without React error #527