stacks: add Kokoro, VibeVoice 1.5B, Chatterbox Turbo (TTS slate fill-in)

Three TTS additions to round out coverage on irv-ml1, each filling a
distinct niche the existing slate doesn't own.

Final coverage matrix (all on irv-ml1):
  Kokoro              — low-latency English, fixed voice library, ~300ms TTFA
  Chatterbox Turbo    — low-latency English w/ voice cloning + paralinguistic tags
  IndexTTS-2          — English voice cloning + emotion vector / text control
  Qwen3-TTS-1.7B-Base — high-quality English voice cloning
  CosyVoice 3         — multilingual (Chinese-leaning)
  VibeVoice 1.5B      — long-form / multi-speaker dialogue

stacks/kokoro:
  - port 8193, GPU device 0 (3090)
  - pulls ghcr.io/remsky/kokoro-fastapi-gpu:v0.2.4-master (no Dockerfile,
    no first-run model download — models baked in)
  - 60+ built-in voices, OpenAI-compat with stream=true over chunked HTTP
  - Apache-2.0 weights + code, ~1 GB VRAM

stacks/vibevoice:
  - port 8194, GPU device 1 (A6000 — for 7B headroom)
  - builds groxaxo/VibeVoice-FastAPI1 (more current fork of ncoder-ai)
    pinned to 7614c469a145
  - default model microsoft/VibeVoice-1.5B (~7 GB bf16 VRAM); env var
    swap to rsxdalv/VibeVoice-Large (7B) or FabioSarracino/VibeVoice-Large-Q8
  - multi-speaker dialogue via /v1/vibevoice/generate with Speaker N: format
  - long-form niche only — not low-latency

stacks/chatterbox:
  - port 8196, GPU device 0 (3090)
  - builds devnen/Chatterbox-TTS-Server (most active Turbo-supporting wrapper)
  - default model ResembleAI/chatterbox-turbo (~2.5 GB fp16, ~75ms latency)
  - paralinguistic tags inline ([laugh] [whisper] etc) — different shape
    from IndexTTS-2's emotion vector; fills the speed+cloning niche
    Kokoro/IndexTTS don't cover together
  - mandatory PerTh watermark on outputs (Resemble policy)

Three matching playbooks under playbooks/deploy-{kokoro,vibevoice,
chatterbox}.yaml. All idempotent, creates-/when-gated.

Cold-deploy disk on /worktank/: ~7 GB Kokoro + ~19 GB VibeVoice 1.5B
+ ~12 GB Chatterbox = ~38 GB total. VRAM concurrent: ~10-11 GB across
both GPUs.

Skipped from the original four-stack proposal: VibeVoice Realtime
(overlaps Kokoro's niche; Kokoro wins on latency, license, and not
needing a build).

stacks/kokoro/compose.yaml

@@ -0,0 +1,52 @@
+# Kokoro-82M served via remsky/Kokoro-FastAPI — the de-facto OpenAI-
+# compatible wrapper for hexgrad's Kokoro-82M TTS.
+#
+# Why this stack exists alongside the other TTS:
+#   * Lowest-latency English in the fleet — ~300 ms TTFA on GPU,
+#     RTF 35-100x on a 4060 Ti class card.
+#   * Native streaming via OpenAI-compat `stream=true` over HTTP
+#     chunked transfer (Kokoro's KPipeline is a per-phrase generator).
+#   * Apache-2.0 weights + code; ~1 GB VRAM at fp16.
+#   * 60+ built-in voices (no cloning — for that use IndexTTS-2 or
+#     Chatterbox Turbo). Voices combinable via "voice(weight)+..." syntax.
+#
+# Image is a published GHCR build; no Dockerfile to maintain. Models
+# baked into the image, no first-run download. Deploy is a pull + up.
+#
+# All tunables live in .env — edit that, not this file.
+
+services:
+  kokoro:
+    image: ghcr.io/remsky/kokoro-fastapi-gpu:${KOKORO_TAG}
+    container_name: kokoro
+    restart: unless-stopped
+    runtime: nvidia
+    ports:
+      - "${KOKORO_BIND:-0.0.0.0}:${KOKORO_PORT}:8880"
+    environment:
+      - NVIDIA_VISIBLE_DEVICES=${KOKORO_GPU_DEVICES:-0}
+      - USE_GPU=true
+      - API_LOG_LEVEL=${KOKORO_LOG_LEVEL:-INFO}
+    volumes:
+      # Optional voice-overlay mount — drop a custom <name>.pt into the
+      # host dir to make it available alongside the 60+ built-ins. The
+      # image already ships voicepacks at this path, so the bind mount
+      # SHADOWS them — only do this if you actually want to manage the
+      # full voice library yourself. For most deploys, leave the mount
+      # commented out and use the in-image voices.
+      # - ${KOKORO_VOICES_DIR}:/app/api/src/voices/v1_0
+      - ${KOKORO_USER_VOICES_DIR}:/app/user_voices
+    healthcheck:
+      # The image is python-based with curl available. /v1/audio/voices
+      # is a no-arg GET that exercises the full API path.
+      test: ["CMD-SHELL", "curl -fsS -o /dev/null http://localhost:8880/v1/audio/voices || exit 1"]
+      interval: 30s
+      timeout: 10s
+      retries: 3
+      start_period: 90s
+    labels:
+      - homepage.group=AI Systems
+      - homepage.name=Kokoro
+      - homepage.icon=mdi-microphone-message
+      - homepage.description=Low-latency English TTS w/ streaming (irv-ml1)
+      - homepage.href=http://10.100.79.3:${KOKORO_PORT}