Add force meeting mode hotkey

[xAlcahest]

Summary

• Add a dedicated hotkey (Ctrl+Shift+M by default) to manually start meeting mode, skipping the automatic "Meeting Detected" notification
• Same hotkey toggles meeting mode off
• While manual meeting mode is active, automatic meeting detection notifications are suppressed
• Hotkey is configurable in Settings → Hotkeys
• Meeting hotkey persisted to .env across restarts
• i18n strings added across all 9 supported languages

[gabrielste1n]

Thanks for the contribution! We went in a slightly different direction with this feature — implemented in feature/meeting-mode-hotkey as a one-way trigger rather than a toggle.

Key differences:

• No toggle state: The hotkey starts meeting mode; the user stops recording normally (no second press needed, no _manualMeetingMode flag)
• No detection suppression logic: The existing _userRecording flag already suppresses auto-detection while recording, so no additional state management is needed
• No extra IPC handles: Since the hotkey fires directly in main.js, the force-meeting-mode / end-manual-meeting-mode IPC endpoints aren't required
• No default hotkey: Starts empty to avoid stealing keybindings from other apps

Appreciate the i18n coverage and the clean hotkey registration pattern — both informed the final implementation.