std: remove error.BrokenPipe from file reads, add error.EndOfStream

and make reading file streaming allowed to return 0 byte reads.
According to Microsoft documentation, on Windows it is possible to get
0-byte reads from pipes when 0-byte writes are made.
f612d5ae96Andrew Kelley committed on 1/27/2026, 11:33:46 PMparent46b5eb6
6 files changedLine totals unavailable