feat(windows): Native AMD ROCm GPU Acceleration (Resolves #531) (#538)

* feat(windows): add native ROCm support for AMD GPUs

Implements native ROCm architecture for Windows.

- Adds backend build pipeline for voicebox-server-rocm.exe

- Detects AMD GPUs dynamically and routes PyTorch allocations

- Adds automatic download and update logic for ROCm dependencies

- Refactors UI in GpuPage.tsx and GpuAcceleration.tsx to add AMD flows

- Fixes 'Switch to CPU' lock on Windows via Tauri backend_override state

- Resolves PyInstaller/rocm_sdk UnboundLocalError silent crashes

- Resolves Numba/NumPy 2.x incompatibilities during Qwen3-TTS load

- Resolves HF_HUB_OFFLINE Catch-22 for CustomVoice processor caching

* fix(rocm): host libs archive under the app release tag, drop offline-load regression

Align the ROCm libs download with the CUDA pattern: both the server core and
the libs archive are published under the app-version release tag, with the libs
content version encoded in the filename only. The previous code fetched libs
from a separate rocm7.2-v1 tag, which disagreed with the download test.

Also revert the unrelated Qwen CustomVoice changes that wrapped model loading in
force_offline_if_cached (not imported — a NameError on load for every platform)
and re-added a Base-model cache gate. The inference-path offline guard was
deliberately removed previously.

* feat(rocm): gate download on AMD detection and persist the backend variant

The ROCm download section now only shows when the backend reports an AMD GPU on
Windows (new supports_rocm health field, backed by the memoized
is_amd_gpu_windows detection that was previously unused), or when ROCm is already
downloaded/active.

Make the backend override honor a pinned variant: set_backend_override persists
the choice to disk so it survives an app restart, start_server reads it back,
and a cuda/rocm pin now actually selects that variant instead of always
preferring ROCm. A stale pin to a deleted backend self-heals to the default
order rather than forcing CPU. Add the web no-op stub for the new method.

* chore(rocm): drop incomplete vitest harness for the unused GpuAcceleration component

GpuAcceleration.tsx is not routed anywhere (GpuPage is the live settings view),
and the added vitest setup referenced testing-library/vitest deps that were not
in the lockfile, breaking the web typecheck. Remove the dead component's test
and its scaffolding to keep this PR scoped to the ROCm feature.

* ci(rocm): add ROCm release-artifact pipeline

Mirror the CUDA packaging path for ROCm so the runtime download has artifacts to
fetch. scripts/package_rocm.py splits the PyInstaller --rocm onedir into
voicebox-server-rocm.tar.gz (core) + rocm-libs-rocm7.2-v1.tar.gz (AMD runtime:
HIP DLLs, rocBLAS Tensile data, MIOpen kernel DBs) + rocm-libs.json, matching
the names services/rocm.py expects, both under the app-version release tag.

The new build-rocm-windows job in release.yml builds on windows-latest/cp312 and
lets build_binary.py --rocm pull the official AMD Radeon wheels.

The file classifier can't be validated against a real AMD build on CI, so it has
unit coverage (test_package_rocm.py) against a synthetic onedir layout. The
prefixes/dir markers may need a tweak after the first real build on AMD
hardware — the packager hard-fails loudly if it classifies zero ROCm files.

---------

Co-authored-by: Jamie Pine <[email protected]>

backend/routes/__init__.py

@@ -20,6 +20,7 @@ def register_routers(app: FastAPI) -> None:
     from .settings import router as settings_router
     from .tasks import router as tasks_router
     from .cuda import router as cuda_router
+    from .rocm import router as rocm_router
     from .speak import router as speak_router
     from .mcp_bindings import router as mcp_bindings_router
     from .events import router as events_router
@@ -39,6 +40,7 @@ def register_routers(app: FastAPI) -> None:
     app.include_router(settings_router)
     app.include_router(tasks_router)
     app.include_router(cuda_router)
+    app.include_router(rocm_router)
     app.include_router(speak_router)
     app.include_router(mcp_bindings_router)
     app.include_router(events_router)

backend/routes/health.py

@@ -13,7 +13,7 @@ from sqlalchemy.orm import Session
 from .. import config, models
 from ..services import tts
 from ..database import get_db
-from ..utils.platform_detect import get_backend_type
+from ..utils.platform_detect import get_backend_type, is_amd_gpu_windows
 
 router = APIRouter()
 
@@ -103,7 +103,10 @@ async def health():
 
     gpu_type = None
     if has_cuda:
-        gpu_type = f"CUDA ({torch.cuda.get_device_name(0)})"
+        if hasattr(torch.version, "hip") and torch.version.hip:
+            gpu_type = f"ROCm ({torch.cuda.get_device_name(0)})"
+        else:
+            gpu_type = f"CUDA ({torch.cuda.get_device_name(0)})"
     elif has_mps:
         gpu_type = "MPS (Apple Silicon)"
     elif backend_type == "mlx":
@@ -164,6 +167,15 @@ async def health():
     except Exception:
         pass
 
+    default_variant = "cpu"
+    if has_cuda:
+        if hasattr(torch.version, "hip") and torch.version.hip:
+            default_variant = "rocm"
+        else:
+            default_variant = "cuda"
+    elif has_xpu:
+        default_variant = "xpu"
+
     return models.HealthResponse(
         status="healthy",
         model_loaded=model_loaded,
@@ -173,10 +185,8 @@ async def health():
         gpu_type=gpu_type,
         vram_used_mb=vram_used,
         backend_type=backend_type,
-        backend_variant=os.environ.get(
-            "VOICEBOX_BACKEND_VARIANT",
-            "cuda" if torch.cuda.is_available() else ("xpu" if has_xpu else "cpu"),
-        ),
+        backend_variant=os.environ.get("VOICEBOX_BACKEND_VARIANT", default_variant),
+        supports_rocm=is_amd_gpu_windows(),
         gpu_compatibility_warning=gpu_compat_warning,
     )
 

backend/routes/rocm.py

@@ -0,0 +1,79 @@
+"""ROCm backend management endpoints."""
+
+import logging
+
+from fastapi import APIRouter, HTTPException
+from fastapi.responses import StreamingResponse
+
+from ..services.task_queue import create_background_task
+from ..utils.progress import get_progress_manager
+
+router = APIRouter()
+
+logger = logging.getLogger(__name__)
+
+
+@router.get("/backend/rocm-status")
+async def get_rocm_status():
+    """Get ROCm backend download/availability status."""
+    from ..services import rocm
+
+    return rocm.get_rocm_status()
+
+
+@router.post("/backend/download-rocm")
+async def download_rocm_backend():
+    """Download the ROCm backend binary."""
+    from ..services import rocm
+
+    progress_manager = get_progress_manager()
+    existing = progress_manager.get_progress(rocm.PROGRESS_KEY)
+    if existing and existing.get("status") in {"downloading", "extracting"}:
+        raise HTTPException(status_code=409, detail="ROCm backend download already in progress")
+
+    async def _download():
+        try:
+            await rocm.download_rocm_binary()
+        except Exception as e:
+            logger.error("ROCm download failed: %s", e)
+
+    create_background_task(_download())
+    return {"message": "ROCm backend download started", "progress_key": rocm.PROGRESS_KEY}
+
+
+@router.delete("/backend/rocm")
+async def delete_rocm_backend():
+    """Delete the downloaded ROCm backend binary."""
+    from ..services import rocm
+
+    if rocm.is_rocm_active():
+        raise HTTPException(
+            status_code=409,
+            detail="Cannot delete ROCm backend while it is active. Switch to CPU first.",
+        )
+
+    deleted = await rocm.delete_rocm_binary()
+    if not deleted:
+        raise HTTPException(status_code=404, detail="No ROCm backend found to delete")
+
+    return {"message": "ROCm backend deleted"}
+
+
+@router.get("/backend/rocm-progress")
+async def get_rocm_download_progress():
+    """Get ROCm backend download progress via Server-Sent Events."""
+    progress_manager = get_progress_manager()
+
+    async def event_generator():
+        async for event in progress_manager.subscribe("rocm-backend"):
+            yield event
+
+    return StreamingResponse(
+        event_generator(),
+        media_type="text/event-stream",
+        headers={
+            "Cache-Control": "no-cache",
+            "Connection": "keep-alive",
+            "X-Accel-Buffering": "no",
+        },
+    )