Task 1b — Speak "I didn't quite catch that" via TTS on low confidence

Task 1b — TTS response for low-confidence transcript

Part of Task 1: Low Confidence Voice Feedback. Depends on #373 (Task 1a).

What to do

Using the low-confidence event surfaced in Task 1a, trigger a TTS response when Whisper confidence falls below the rejection threshold.

• In src/jarvis/reply/ or wherever the listener dispatches results, handle the low-confidence event.
• Call the TTS engine (in src/jarvis/output/) to say a short phrase such as "I didn't quite catch that" or "Sorry, could you repeat that?".
• The phrase should ideally be a constant or config value, not hardcoded inline.
• Do not speak this if Jarvis is already speaking or in cooldown (respect existing TTS guard logic).

Files to touch

• src/jarvis/reply/ (dispatch/handler)
• src/jarvis/output/tts.py (if a new helper method is needed)

Acceptance criteria

• Jarvis speaks an audible response when confidence is too low
• Response phrase is a named constant (not a magic string inline)
• Does not double-speak if TTS is already active
• No TTS triggered for normal successful transcripts