fix(phase-1): implement URL materialization and add requests dep

pyproject.toml

@@ -33,6 +33,9 @@ dependencies = [
 
     # UI (Gradio 5.x)
     "gradio>=5.0.0",
+
+    # Networking
+    "requests>=2.0.0",
 ]
 
 [dependency-groups]

src/stroke_deepisles_demo/data/staging.py

@@ -123,9 +123,14 @@ def _materialize_nifti(source: Path | str | bytes | Any, dest: Path) -> None:
         shutil.copy2(source, dest)
     elif isinstance(source, str):
         if source.startswith(("http://", "https://")):
-            # TODO: Implement download logic or use requests
-            # For now, we assume we don't hit this in offline tests
-            raise NotImplementedError("URL download not yet implemented")
+            import requests
+
+            # Download the file
+            response = requests.get(source, stream=True, timeout=30)
+            response.raise_for_status()
+            with dest.open("wb") as f:
+                for chunk in response.iter_content(chunk_size=8192):
+                    f.write(chunk)
         else:
             # Assume local path string
             src_path = Path(source)

uv.lock

@@ -2134,6 +2134,7 @@ dependencies = [
     { name = "numpy" },
     { name = "pydantic" },
     { name = "pydantic-settings" },
+    { name = "requests" },
 ]
 
 [package.dev-dependencies]
@@ -2156,6 +2157,7 @@ requires-dist = [
     { name = "numpy", specifier = ">=1.26.0" },
     { name = "pydantic", specifier = ">=2.5.0" },
     { name = "pydantic-settings", specifier = ">=2.1.0" },
+    { name = "requests", specifier = ">=2.0.0" },
 ]
 
 [package.metadata.requires-dev]