fix(armada/serve): swallow client-disconnect on media Range seek

copyfile() threw BrokenPipeError/ConnectionResetError (Errno 104) when a
browser aborts/seeks a Range request mid-stream — normal for <audio>
scrubbing, but it spammed a traceback. Wrap both copy branches and close
the file handle in a finally. Verified: mid-stream abort leaves no
traceback and the server keeps serving (206 follow-up OK).

armada/serve.py

@@ -127,17 +127,26 @@ class RangeHandler(SimpleHTTPRequestHandler):
         return _LimitedReader(f, length)
 
     def copyfile(self, source, outputfile):
-        if isinstance(source, _LimitedReader):
-            remaining = source.remaining
-            while remaining > 0:
-                chunk = source.read(min(64 * 1024, remaining))
-                if not chunk:
-                    break
-                outputfile.write(chunk)
-                remaining -= len(chunk)
-            source.close()
-        else:
-            super().copyfile(source, outputfile)
+        # A client that seeks/aborts a media Range request mid-stream raises
+        # BrokenPipeError/ConnectionResetError on the next write. That's normal
+        # for <audio> scrubbing, not a failure — swallow it (no traceback), but
+        # still close the file handle.
+        try:
+            if isinstance(source, _LimitedReader):
+                try:
+                    remaining = source.remaining
+                    while remaining > 0:
+                        chunk = source.read(min(64 * 1024, remaining))
+                        if not chunk:
+                            break
+                        outputfile.write(chunk)
+                        remaining -= len(chunk)
+                finally:
+                    source.close()
+            else:
+                super().copyfile(source, outputfile)
+        except (BrokenPipeError, ConnectionResetError):
+            pass
 
 
 class _LimitedReader: