Rename download function's Callable argument

Rename from progress_consumer to progress_subscriber, for two reasons:

1. Consistency with Builder's subscribe_output, subscribe_error, and
   subscribe_progress functions, which accept "subscriber" objects.

2. There is an existing type alias ProgressConsumer used by the
   Builder#subscribe_progress reporting, but the Callable argument
   of download is *not* the same type as this type alias: it's
   Callable[[int, int], None], not Callable[[str, int, int], None].

See also apposed/appose-java@ac5bb38

Author: ctrueden

src/appose/util/download.py

@@ -27,15 +27,15 @@
 def download(
     name: str,
     url_path: str,
-    progress_consumer: Callable[[int, int], None] | None = None,
+    progress_subscriber: Callable[[int, int], None] | None = None,
 ) -> Path:
     """
     Download a file from a URL to a temporary file.
 
     Args:
         name: Base name for the temporary file.
         url_path: The URL to download from.
-        progress_consumer: Optional callback to track download progress (current, total).
+        progress_subscriber: Optional callback to track download progress (current, total).
 
     Returns:
         Path to the downloaded temporary file.
@@ -97,8 +97,8 @@ def download(
                     f.write(chunk)
                     downloaded += len(chunk)
 
-                    if progress_consumer:
-                        progress_consumer(downloaded, file_size)
+                    if progress_subscriber:
+                        progress_subscriber(downloaded, file_size)
 
         # Verify download completed
         if temp_file.stat().st_size < file_size: