Voice Push-to-Talk (Space) inserts spaces instead of only recording

Description

Voice Push-to-Talk with Space key no longer works correctly. When holding Space to record, it simultaneously inserts space characters into the chat input, causing the dB indicator to drift to the right.

Steps to Reproduce

1. Enable voice mode (/voice)
2. Hold Space (Push-to-Talk) to record
3. Observe that space characters are being inserted into the input while recording

Expected Behavior

Previously, after ~3 space characters, Claude Code detected the key was being held down and stopped inserting spaces — only showing the dB recording indicator. Recording worked correctly.

Actual Behavior

• Space characters are continuously inserted into the chat input while holding Space
• The dB recording symbol moves/drifts to the right due to the inserted spaces
• macOS shows microphone access is active (recording starts), but the input is disrupted by the spaces
• Transcription does not work properly due to the space spam

Environment

• macOS (Darwin 25.3.0)
• Claude Code CLI (Terminal)
• Voice dictation language: de

Additional Context

This is a regression — Push-to-Talk with Space worked correctly before. No custom keybindings are set. Adding a custom "space": "voice:pushToTalk" binding did not help (and caused double-binding issues).