fix: improve Windows text insertion and expire cloud retries

[MusicMaster4]

Summary

• Improves Windows text insertion with foreground-app-aware paste shortcuts, modifier handling, and a clipboard-free typing fallback.
• Detects blocked or partial native keyboard injection instead of reporting a false success.
• Expires saved cloud transcription retries after one hour and keeps the renderer state in sync.

Validation

• Windows x64 build
• macOS Intel build
• macOS Apple-Silicon build
• npm run check
• PowerShell parser validation for scripts/send_text.ps1
• Startup error isolation test
• Audio duck/restore regression test

Notes

The original title and description referred to release versioning from an earlier branch state. They were updated to match the actual PR diff.