[BUG] Voice mode: transient spaces inserted in input before hold-Space registers as recording

Description

When using /voice mode in the terminal CLI, holding Space to start recording briefly inserts space characters into the input field before the key press is recognized as the push-to-talk gesture. The spaces are then removed once recording begins, but the visual flicker is distracting and feels unpolished.

Steps to reproduce

1. Start Claude Code in the terminal (not VS Code integrated terminal)
2. Run /voice to enable voice mode
3. Hold the Space bar to begin recording
4. Observe: one or more space characters briefly appear in the input area before the recording indicator activates

Expected behavior

Holding Space should immediately trigger recording without inserting any characters into the input field.

Actual behavior

Space characters are transiently inserted into the input, then cleared when the hold gesture is recognized as push-to-talk. This creates a visible flicker each time recording is initiated.

Possible improvement

Consider allowing the push-to-talk key to be rebound via /keybindings so users can choose a key that doesn't conflict with text input (e.g., a modifier key or function key).

Environment

• Claude Code CLI (terminal, not IDE)
• Ghostty terminal
• macOS Tahoe (latest)