Full extension audit + fix CI/CD for desktop app build #4022

Originally written by @ccantynz-alt on GitHub.
Imported from https://github.com/ccantynz-alt/48co.v1/pull/15

Summary

• Full audit and rewrite of all 4 extension files — 22 bugs fixed (state machine, message routing, text insertion, timeouts, error handling)
• Fixed CI/CD pipeline — removed dependency on missing package-lock.json, added PR trigger
• Middle-click fix — switched from mousedown to auxclick so scrolling doesn't trigger recording
• Text insertion — 3 fallback methods for ProseMirror editors (Claude, ChatGPT)
• Background.js — now tracks which tab started recording, sends results to correct tab

Next step after merge

Merge this to main to trigger the GitHub Actions build that produces:

• 48co-mac.dmg (macOS installer)
• 48co-win.exe (Windows installer)

The desktop app is the primary product — it types into ANY app via global hotkey, matching WhisperTyping/Wispr Flow.

Test plan

• Merge to main
• Verify GitHub Actions build triggers and produces .dmg and .exe
• Download and test on Windows
• Download and test on macOS
• Verify global hotkey (Ctrl+Shift+Space) starts recording
• Verify Whisper API transcription works with API key
• Verify text types into focused application

https://claude.ai/code/session_01PBeNmPHrD2W6A2YKZRC7V3