Add language selector for built-in voice dictation

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Summary

The microphone button in the Claude Code desktop app has no way to choose the recognition language. The dropdown next to the mic only exposes input device selection and a "Hold to record" toggle.

Current behavior

• Built-in dictation appears to be English-only (or auto-detect with no override).
• Non-English speakers cant reliably dictate prompts in their native language.

Expected behavior

• A language picker in the same dropdown as microphone selection (e.g. English / Russian / Spanish / ... / Auto-detect).
• Optionally: respect OS input language by default.

Comparison

The Claude extension for VS Code already supports switching the dictation language — desktop Claude Code should reach parity.

Environment

• OS: Windows 11 Pro
• Claude Code: desktop app
• Model: Opus 4.7 (1M context)

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