fix(upscaler): show_error=True + handle_file for local paths + clearer errors

- graph.launch(show_error=True) so node exceptions show real message
- Use handle_file(path) for all paths so Phips/Upscaler receives file content (remote server cannot read local path)
- Wrap Client.predict in try/except with RuntimeError for clearer Upscaler API errors

Co-authored-by: Cursor <cursoragent@cursor.com>

app.py

@@ -41,10 +41,16 @@ def run_upscaler(image, model_selection="4xBHI_dat2_real"):
     path = _image_to_filepath(image)
     if not path:
         return None
-    client = Client("Phips/Upscaler")
-    # API expects (image: filepath, model_selection: str). Use handle_file for URLs, path string for local paths.
-    image_arg = handle_file(path) if path.startswith("http") else path
-    result = client.predict(image_arg, model_selection, api_name="/upscale_image")
+    # Phips/Upscaler runs on a different server - send file content via handle_file so it can read the image (local path is not visible there).
+    try:
+        image_arg = handle_file(path)
+    except Exception as e:
+        raise RuntimeError(f"Upscaler: could not load image from path: {e}") from e
+    try:
+        client = Client("Phips/Upscaler")
+        result = client.predict(image_arg, model_selection, api_name="/upscale_image")
+    except Exception as e:
+        raise RuntimeError(f"Upscaler API error: {e}") from e
     # Returns tuple of 2: [comparison, filepath]; we need the upscaled image path (second element)
     if result and len(result) >= 2 and result[1]:
         return result[1]
@@ -117,5 +123,5 @@ graph = Graph(
     ],
 )
 
-# Launch the Space
-graph.launch()
+# Launch the Space (show_error=True so node exceptions show the real message)
+graph.launch(show_error=True)