feat(omnivoice): streaming /tts + language-safe sanitizer

Add a live-consumer streaming path and text sanitation to the OmniVoice
wrapper, so it can front speech-to-speech chat engines (not just the
asset-engine's batch WAV use).

- POST /tts: chunked 24 kHz mono s16le PCM (or open-ended WAV), driven by
  the adaptive buffer-ratchet scheduler. Emits the first sentence
  immediately, then ratchets chunk size up on OmniVoice's ~40x realtime
  headroom -> sub-second time-to-first-audio. Wire-compatible with
  chatterbox-fast /tts (both 24 kHz mono PCM). Batch /v1/audio/speech is
  unchanged for asset/file callers.

- scheduler.py: VENDORED byte-faithful copy of chatterbox-fast's pure-
  Python (torch-free) scheduler, pinned to commit 7631462 (v0.1.0/v0.1.1).
  Vendor-copy over a shared package (operator call 2026-06-19): the module
  has no GPU deps, so reuse it without dragging chatterbox-fast's torch
  tree into this image. Promote to a shared package only on a 3rd consumer
  or real drift.

- sanitize.py: language-safe TTS sanitizer run on both endpoints. Strips
  markdown, <think> blocks, HTML, and model control tokens; deliberately
  SKIPS the fork's English-only number/phone normalization that would
  corrupt OmniVoice's 600-language input. Preserves [laughter]-style tags.

- Refactor: shared GenParams base for SpeechRequest + TTSStreamRequest;
  single GEN_LOCK serializes generation (single-stream interactive).

- Dockerfile/playbook: copy + upload the two new modules; build-time
  `import app` smoke; correct stale "Gradio demo / no FastAPI" comments.

playbooks/deploy-omnivoice.yaml

@@ -1,11 +1,12 @@
 # Deploy OmniVoice (https://github.com/k2-fsa/OmniVoice) to irv-ml1, GPU 0
 # (RTX 3090). Apache-2.0 zero-shot multilingual voice-cloning TTS, served
-# via upstream's own Gradio demo (no FastAPI wrapper).
+# behind our OWN FastAPI wrapper (app.py): batch /v1/audio/speech plus a
+# streaming /tts driven by the vendored buffer-ratchet scheduler.
 #
 # Builds the image locally from stacks/omnivoice/Dockerfile (CUDA 12.8 +
-# torch 2.8.0 + omnivoice from PyPI), stages the build context under
-# /opt/docker/compose/omnivoice/, brings it up, and waits for the Gradio
-# UI on :8199.
+# torch 2.8.0 + omnivoice from PyPI + vendored scheduler.py/sanitize.py),
+# stages the build context under /opt/docker/compose/omnivoice/, brings it
+# up, and waits for /healthz on :8199.
 #
 # First run is slow: ~5-10 min docker build + a one-time HF weight pre-warm
 # (k2-fsa/OmniVoice) on first container start (entrypoint.sh). The wait loop
@@ -61,12 +62,24 @@ steps:
       dest: "{{ compose_dir }}/Dockerfile"
       mode: "0644"
 
-  - name: Upload app.py (asset-engine FastAPI wrapper)
+  - name: Upload app.py (batch + streaming FastAPI wrapper)
     upload:
       src: stacks/omnivoice/app.py
       dest: "{{ compose_dir }}/app.py"
       mode: "0644"
 
+  - name: Upload scheduler.py (vendored buffer-ratchet streaming scheduler)
+    upload:
+      src: stacks/omnivoice/scheduler.py
+      dest: "{{ compose_dir }}/scheduler.py"
+      mode: "0644"
+
+  - name: Upload sanitize.py (language-safe TTS text sanitizer)
+    upload:
+      src: stacks/omnivoice/sanitize.py
+      dest: "{{ compose_dir }}/sanitize.py"
+      mode: "0644"
+
   - name: Stage chatterbox reference voices for cloning (skip _*.wav artifacts)
     shell: |
       set -e