fix: default distributions to automatic GPU support with CPU fallback

tools/embeddinggemma2/build_runtime.py

@@ -17,7 +17,7 @@ def run(arguments, cwd=None):
 
 def main():
     parser = argparse.ArgumentParser(description="Build Searchi's pinned Google embedding worker")
-    parser.add_argument("--backend", choices=["cpu", "auto", "metal", "vulkan", "cuda"], default="cpu")
+    parser.add_argument("--backend", choices=["cpu", "auto", "metal", "vulkan", "cuda"], default="auto")
     parser.add_argument("--jobs", type=int, default=2)
     args = parser.parse_args()
     if not 1 <= args.jobs <= 16:

tools/embeddinggemma2/stage_runtime.py

@@ -25,7 +25,7 @@ def verify_bundle(root, manifest):
 
 def main():
     parser = argparse.ArgumentParser(description="Stage Searchi runtime resources")
-    parser.add_argument("--backend", choices=["cpu", "auto", "metal", "vulkan", "cuda"], default="cpu")
+    parser.add_argument("--backend", choices=["cpu", "auto", "metal", "vulkan", "cuda"], default="auto")
     parser.add_argument("--bundle-model", action="store_true")
     args = parser.parse_args()
     name = "searchi-gemma-worker.exe" if os.name == "nt" else "searchi-gemma-worker"

tools/embeddinggemma2/test_stage_runtime.py

@@ -32,7 +32,7 @@ class StagingTests(unittest.TestCase):
                 (models / filename).write_bytes(content)
                 specs.append({"path": filename, "bytes": len(content), "sha256": hashlib.sha256(content).hexdigest()})
             (models / "projector.gguf").write_bytes(b"corrupt!")
-            with patch.object(stage_runtime, "ROOT", root), patch("sys.argv", ["stage_runtime", "--bundle-model"]), patch.object(stage_runtime.json, "loads", return_value={"files": specs}):
+            with patch.object(stage_runtime, "ROOT", root), patch("sys.argv", ["stage_runtime", "--backend", "cpu", "--bundle-model"]), patch.object(stage_runtime.json, "loads", return_value={"files": specs}):
                 with self.assertRaisesRegex(RuntimeError, "checksum mismatch"):
                     stage_runtime.main()
             self.assertEqual((destination / name).read_bytes(), b"previous worker")