feat: add NeuTTS optional skill + local TTS provider backend

* feat(skills): add bundled neutts optional skill

Add NeuTTS optional skill with CLI scaffold, bootstrap helper, and
sample voice profile. Also fixes skills_hub.py to handle binary
assets (WAV files) during skill installation.

Changes:
- optional-skills/mlops/models/neutts/ — skill + CLI scaffold
- tools/skills_hub.py — binary asset support (read_bytes, write_bytes)
- tests/tools/test_skills_hub.py — regression tests for binary assets

* feat(tts): add NeuTTS as local TTS provider backend

Add NeuTTS as a fourth TTS provider option alongside Edge, ElevenLabs,
and OpenAI. NeuTTS runs fully on-device via neutts_cli — no API key
needed.

Provider behavior:
- Explicit: set tts.provider to 'neutts' in config.yaml
- Fallback: when Edge TTS is unavailable and neutts_cli is installed,
  automatically falls back to NeuTTS instead of failing
- check_tts_requirements() now includes NeuTTS in availability checks

NeuTTS outputs WAV natively. For Telegram voice bubbles, ffmpeg
converts to Opus (same pattern as Edge TTS).

Changes:
- tools/tts_tool.py — _generate_neutts(), _check_neutts_available(),
  provider dispatch, fallback logic, Opus conversion
- hermes_cli/config.py — tts.neutts config defaults

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Co-authored-by: unmodeled-tyler <unmodeled.tyler@proton.me>

optional-skills/mlops/models/neutts/assets/neutts-cli/samples/jo.txt

@@ -0,0 +1 @@
+So I just tried Neuphonic and I’m genuinely impressed. It's super responsive, it sounds clean, supports voice cloning, and the agent feature is fun to play with too. Highly recommend it for podcasts, conversations, or even just messing around with voiceovers.