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]>

app/src/lib/api/client.ts

@@ -20,6 +20,7 @@ import type {
   PresetVoice,
   PersonalityTextResponse,
   ProfileSampleResponse,
+  RocmStatus,
   StoryCreate,
   StoryDetailResponse,
   StoryItemBatchUpdate,
@@ -693,6 +694,23 @@ class ApiClient {
     });
   }
 
+  // ROCm Backend Management
+  async getRocmStatus(): Promise<RocmStatus> {
+    return this.request<RocmStatus>('/backend/rocm-status');
+  }
+
+  async downloadRocmBackend(): Promise<{ message: string; progress_key: string }> {
+    return this.request<{ message: string; progress_key: string }>('/backend/download-rocm', {
+      method: 'POST',
+    });
+  }
+
+  async deleteRocmBackend(): Promise<{ message: string }> {
+    return this.request<{ message: string }>('/backend/rocm', {
+      method: 'DELETE',
+    });
+  }
+
   // Stories
   async listStories(): Promise<StoryResponse[]> {
     return this.request<StoryResponse[]>('/stories');

app/src/lib/api/models/ModelStatus.ts

@@ -9,7 +9,7 @@ export type ModelStatus = {
   model_name: string;
   display_name: string;
   downloaded: boolean;
-  downloading?: boolean;  // True if download is in progress
+  downloading?: boolean; // True if download is in progress
   size_mb?: number | null;
   loaded?: boolean;
 };

app/src/lib/api/types.ts

@@ -269,7 +269,8 @@ export interface HealthResponse {
   gpu_type?: string;
   vram_used_mb?: number;
   backend_type?: string;
-  backend_variant?: string; // "cpu" or "cuda"
+  backend_variant?: string; // "cpu", "cuda", or "rocm"
+  supports_rocm?: boolean; // AMD GPU on Windows — the ROCm backend is applicable
 }
 
 export interface CudaDownloadProgress {
@@ -291,6 +292,26 @@ export interface CudaStatus {
   download_progress?: CudaDownloadProgress;
 }
 
+export interface RocmDownloadProgress {
+  model_name: string;
+  current: number;
+  total: number;
+  progress: number;
+  filename?: string;
+  status: 'downloading' | 'extracting' | 'complete' | 'error';
+  timestamp: string;
+  error?: string;
+}
+
+export interface RocmStatus {
+  available: boolean; // ROCm binary exists on disk
+  active: boolean; // Currently running the ROCm binary
+  binary_path?: string;
+  rocm_libs_version?: string;
+  downloading: boolean; // Download in progress
+  download_progress?: RocmDownloadProgress;
+}
+
 export interface ModelProgress {
   model_name: string;
   current: number;