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

---------

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

optional-skills/mlops/models/neutts/assets/neutts-cli/README.md

@@ -0,0 +1,55 @@
+# NeuTTS CLI
+
+Small standalone CLI for installing, checking, and running [NeuTTS](https://github.com/neuphonic/neutts) locally.
+
+This scaffold is designed to be a good fit for a future Hermes optional skill:
+
+- predictable commands
+- machine-friendly output for inspection
+- local voice profile management
+- direct local synthesis
+
+## Commands
+
+```bash
+neutts install --all
+neutts doctor
+neutts list-models
+neutts add-voice demo --ref-audio ./samples/jo.wav --ref-text-file ./samples/jo.txt
+neutts list-voices
+neutts synth --voice demo --text Hello from NeuTTS --out ./out.wav
+neutts synth --voice demo --text Quick smoke test
+```
+
+## Install the bundled scaffold
+
+```bash
+cd optional-skills/mlops/models/neutts/assets/neutts-cli
+python -m pip install -e .
+```
+
+## Add the bundled sample profile
+
+This skill bundles an upstream NeuTTS sample reference in `samples/`.
+
+```bash
+cd optional-skills/mlops/models/neutts/assets/neutts-cli
+PYTHONPATH=src python -m neutts_cli.cli add-voice jo-demo \
+  --ref-audio ./samples/jo.wav \
+  --ref-text-file ./samples/jo.txt \
+  --language en
+```
+
+Then inspect it with:
+
+```bash
+PYTHONPATH=src python -m neutts_cli.cli list-voices
+```
+
+## Notes
+
+- `install` installs the upstream `neutts` package into the current Python environment.
+- `list-voices` shows local voice profiles created with `add-voice`.
+- `synth` uses NeuTTS reference cloning. A voice profile is just a saved reference audio/text pair.
+- `synth` accepts quoted or unquoted text and defaults to `./out.wav` when `--out` is omitted.
+- GGUF / `llama-cpp-python` acceleration can vary by platform, so the CLI prints follow-up guidance instead of forcing one build recipe.