Voice mode: global/system-wide hotkey for push-to-talk

Feature Request

Current behavior: Voice mode's push-to-talk key (Space) only works when the Claude Code terminal is focused.

Desired behavior: A system-wide/global hotkey that activates voice recording from any window, without needing to alt-tab to the terminal first.

Why: A major benefit of voice mode is being able to split attention — e.g., reading docs or working in another app while dictating to Claude. Currently, needing to focus the terminal window first negates much of that benefit.

This is a common pattern in voice-driven tools (e.g., Discord, Teams push-to-talk all support global hotkeys).